Ill say it right off the bat the worst nightmare for the borg would be them trying to assimilate an arc mechanicus ship and meeting an old and very very grumpy DAoT AI not taking too kindly to their childish antics waking it up from its power nap.

The Borg are going to hate the Orks

I could see the Borg assimilating elements of The Empire of Man (such as some heavily industrial hive worlds and tech centres) along with the Craftworld Eldar and maybe some Tau worlds and Necron Tomb worlds.  The rest I would expect to either be too different/genetically unstable (such as the Orks, the Tyranids and some chaos cults) or just not worth the effort.  Also, whether the Borg could survive would depend heavily on who they first come into contact with.  If it was an Astartes chapter fleet for example, I would consider their chances to be low.  However, if they were to come upon some human world with little more than militia defending it or some isolated fleet units I can see them getting enough information and resources together in order to adapt before coming into contact with an overwhelming enemy.

The Borg would be a NIGHTMARE in 40K. Their biggest advantage is not their weapons, or number. It's efficiency. The Borg can respond to threats more quickly and with more accuracy than anyone in 40K. Their transwarp is even faster than the 40K warp, allowing them to traverse the galaxy in hours rather than months. They are instantly aware of anything that happens to any of them and can analyze and respond instantly. The Imperium is so bogged in bureaucracy that it takes them a decade to wipe their own @$$, ONCE. The Eldar are either space tweakers or space hobos, the Tyranids can take decades to go from one planet to the next, the Necrons are busy fighting themselves and the Imperium, the Orks are... the Orks, and the Tau would try to open with negotiations.

Also, psykers are no help because there ARE telepathic species in Star Trek. Many of them quite powerful. Technology DOES exist to deal with telepaths. Even the Federation has such technology. Mostly medical in order to treat psychic illnesses.

You are also underestimating Star Trek weapons. Remember, a small handheld weapon the size of a TV remote can literally reduce a human body to NOTHING in a single shot instantly. Many Necron weapons can't even do that. A single Klingon bird of prey can exterminatus a planet. Grated this would take several hours, but it can still do it. A bird of prey is a SMALL SCOUT SHIP. It's meant for raiding and hit and run tactics. It has two disruptor cannons and one photon torpedo launcher with about 15-20 torpedos. It also has a crew of 10-15. Each shot from the disruptor canons is like a nuclear weapon that disrupts atomic bonds. Reducing even large targets to nothing. This weapon sent a cosmic entity running for it's life with two shots. Shields in Star Trek are meant to withstand several shots from such weapons. Most weapons in 40K wouldn't even scratch them.

The Borg ARE vulnerable to kinetic weapons, not because of some weakness. But because of efficiency. 95% of all species they encounter use energy based weapons. It is a waste to equip every drone with a shield that wastes space and energy when it will likely never be used. It's cheaper to loose a few drones to such a surprise tactic and then equip the proper shields than keep them on at all times.

Next, Borg nanoprobes DO self replicate, that's how the assimilation process works. That's how they are able to assimilate and create new construction in such a short time. The Borg even have nanobombs to launch at planets and begin the assimilation process on a planetary level. Yes, drones are required for a lot of the construction, but the foundation is formed by the arrival of the probes. In people, the probes create a base drone, using the victims material to create the basic Borg interfaces so they can be processed into specific drones later. They will not do a full assimilation with nanoprobes because that would eat up too much of the subjects mass and might kill them.

There is also a debate on whether Picard or STOL is the true canon. In STOL the Borg are on the back foot after Voyager but they are far from beaten.

One forgets about the Dark Age of Technology, the Men of Iron, how the War in Heaven did strange things to the Warhammer 40k universe, and technology made by the Emperor of Mankind. Especially Dark Age of Technology is still hoarded away, especially Necron super weapons have been stowed away by the Silent King, and that the Choas Entities LOVE messing with everyone and everything to further their capricious interests. The Borg will SEEK out Dark Age of Technology caches, and thus whether they thrive or not, will be just another species in the grim dark future.

The Borg would SLAY in the 40k verse.

Considering that navel arms men love useing blastic weapions. Like scatter guns, alto rifles borg borders are going to have a bastly suprise
And god help them if the crew uses any pyskers.

God help Tyler and Krista! Prayers for them

I can't do any financial backing for the gofundme, but I can pray for him and his family. May God heal that man swiftly! Thank you for the fun vs video, by the way!

So, would an assimilated ork, be a Bork?

The Borg wouldn’t really put up enough of a fight to please the Orks, but I think the Orks would drool over the Borg cubes, as that’s a lot of scrap to repurpose

goddamn he knew I was opening Stellaris

Can you do the same analysis for stargate?

All the borg would need to do is assimilate some necrons. Once they got a foothold, they have assimilated literal resurrection, and are twice as hard to kill.  Then could just work there way all the way until they controlled the Celestial Orrery. The queen would have no problems using it, to erase the imperium or any other threats they couldnt absord traditionally

The Borg Vrs The Necrons
The Borg have the ONE THING that the necrons want, the ability to INTERFACE WITH FLESH.
Have you forgotten that the necrons desire to return to the Necrontyr? The Borg just need a few cells and they can clone as many new Necrontyr as they wish, or make babies and shake up the DNA to make different bodies. Then it's a one two, skip a few steps and you got the necrons experiencing flesh once again. As proven by what the borg queen did to Data.

Now, how does this go down?

The problem is, who strikes first.

If the Borg strike first, figure out what "living metal" is, then it's game over. The borg ships already are semi-organic, but to go TOTALLY organic? Furthermore, while the Silent King destroyed his command protocals to give the necrons free will again, they existed once, they can again. If the borg got ahole of the silent king, the entire Necro empire is now the bitches of the Borg.

However, if the Necros hear about the Borg FIRST? Ooo... The are gonna organize a strike force from HELL, and silce up every borg ship they can find and tear them apart, molecule by molecule. once they figure out the organic machine interface technology, they will invade the borg and take THEM over, but that ain't happening unless the Necrons have TIME. Again, who jumps who.


The Borg vrs The orcs
The real question is, could the borg figure out the Old One "programing" of the orcs? Because being able to reproduce by spores, Now that sounds nice. EH... Honestly, I see the case for them just ignoring each other.


The Borg vrs the Tyranids.
The Nids want Biomass. The Borg want Technology. They are just two ships passing in the night. There isn't anything useful in the Nid DNA "data banks" that the Borg can't just whip up themselves.


The Borg vrs Chaos
Here's the real question: How much of a soul does the collective have? Now me? I see the Tau as being the example of what happens when you have a "controled" society. They have almost no souls in the Tau, so I assume the Borg, even less so. No souls means that either one injection of scrap code and most cubes go belly up, vrs there is no FOOD among the borg, and Chaos find hanging out with the Borg results in Starving demons.

BUT, what if they DID have souls? If belief equals reality, could the Borg make their own "Waagh Field"? Every Borg "believes" in a Borg God. Is there now a borg god in the warp? Mmmm....

I'm not sure the borg could assimilate necron tech as the borg have shown to struggle with stuff that's extremely outside of their field. Now given time they'll probably caught up but that's gonna take awhile and if the necrons deem them a serious threat what's stopping them A sharing the flesh curse with the borg or B which is arguably worse the celestial orrery the one super weapon that's still online for them? As the only thing holding them back is the order given by the silent king.

The necrons would make short work of these borg
Borg wouldn’t pose a challenge to any of the other factions either

Love your channel too. Great video.

Isn't the Borg Queen just Slaanesh?

You keep saying the Borg would mostly ignore technologically irrelevant species.
However if the collective requires manpower to get a foothold in 40k, that equation changes to assimilating any compatible species regardless of technology. It's simply more resource efficient to assimilate than incubate new drones.