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You see, I don't actually have to make a magic system until book 3, because the protagonist is new to magic as well. No one explains it to him until way later, but don't worry I totally already planned it out and there will surely be no contradicting information once I reveal how it works.

gravity girl, after the 1000th time yeeting her opponents into space: "What? It's effective!"

Love how the first one is arguably common sense. If you have an unstoppable power, why would you beat around the bush and waste time when you could end a fight immediately?

I love hard-ish magic systems where there are definite rules and limitations, but where those aren't necessarily understood fully in-world, nevermind by the reader. This allows both for well-timed reveals and for SEEMING subversions of the established rules. It's really hard to get it right, because it's so easy to shred the suspension of disbelief, but when a writer gets it right... chef kiss

The "Everything is a nail!" problem can also be the counterpoint to another, equally bad problem: "I've never seen a nail before in my life."

In this variation, instead of using the same solution over and over, the character(s) constantly neglect to use previously proven solutions to problems. It is boring when a character uses the same solution over and over, but it's also extremely frustrating when the character DOESN'T do the thing we KNOW they can do that solved the same issue last time!

I love how the Green Lantern has an incredibly powerful ability, but he genuinely uses it to do the lamest things ever, like make a car or giant fists. And his weakness is the color yellow

There is another kind of limitation you can add to magic : danger from being detected. Think Gandalf saying that if he use fire magic, everybody (aka, Sauron and Saruman at least) will know that he is there. Or the way the paradox strikes Mages in the TTRP Mage : the awakening. It's not exactly a physical cost, because it's unpredictable. It's a threat : if the hero use magic, very bad things may happen, and he can't know what because those things have a will.
Thus, such a limitation has another advantage, because it gaves more choices to the writer. It's a "deus ex machina" that is a consistent with the world.

Your last point about showing Level 10 magic while the main character is Level 1 is really on-point, since one of my stories starts with an intense competition between the magic users showing how it can be used on an expert level before revealing a poor young girl in patched clothes watching from behind a fence, wishing she could be one of those people.

One thing in my story is that magic can wipe memories but NOT emotions.

So from the first timeline, one of my characters was quite kind in the first timeline but saw their friends die but after the main character resetted the timeline in order to save all his friends, the character lost memories of the first timeline but is now colder and they even feel a deja vu meeting the main character even though they got no memory of them.

I always write the worldbuilding first. But that usualy ends up with me going way too in-depth, and coming up with historical events and mythical creatures/places/things that end up never actualy making it into the story 😅

The superman thing reminds me... I've had some truly wild conversations with folks who just somehow entirely failed to notice the main conflict, or entire a-plot of a story because they couldn't imagine something like an internal conflict could possibly be the main point.

I remember one guy who swore the main character in a movie had no character arc, and it was literally the entire focus of everything.

0:14 The THUNDER HEIST? AS APPOSED TO THE LIGHTING THIEVERY?

"Everything's a nail" -- or in D&D terms, "I cast Fireball".

"I didn't ask if we were fighting Fire Elementals.  I said, I cast Fireball."

More on-topic, last year I did a Nanowrimo story where curses are literally the residual spirits of the one who died placing them (which is a hard rule), very soft-magicky (limited only by terms intuitive to each curse), and it starts with my main character getting cursed into being a monster (well, more a "magic animal" kind of "monster" but still).  But what made it really challenging is that the first-person POV is from the curse itself, who acts as a second voice in the main character's head that nobody else can perceive or knows about.  Technically this means my POV gets more visibility into the setting's various soft-magic than the character should normally have, but this also doesn't suddenly turn it into a "hard magic" system either, because the curse more or less "used up" its soft-magic abilities on the main character, leaving it constrained in their new body.

For your first example of anti gravity, MHA did a great job balancing their character. She needs to touch the target with the pads on her fingertips, gets severe nausea when she uses it on herself or exceeds the capacity of ~3 tons, and when she cancels the ability by tapping the pads of her fingers together, everything stops being affected

"We come to stories to be delighted by unexpected solutions to tricky problems" I absolutely love this, and will definitely be thinking about it as I continue to write the rest of my first draft

The cultural and legal one made me think "Harry Potter", I've always said "this probably doesn't happen in the US's magic school" they're probably like "as your first class or protection against the dark arts you'll learn the killer spell as such spell is protected by your first and second amendment rights as the basis to enforce your fourth amendment rights"

I love HARD magic systems, there is something special about a rule or condition going full circle, or stretching a law to its absolute limit, the how far can I take this…
I love the idea of challenges not only the protagonist gets to solve, but also the reader as they go along, how some times the reader, based on the set up of the situation, and the rules, can come up with different solutions to problems, how something this are the same the main character chose, or been surprised by a way a ability was used since they weren’t expecting it, but it also makes sense.
Idk why, it’s just so satisfying.

I don’t know why, but for some reason, I love over-powered characters. For instance, I always got super annoyed when Goku wasn’t around when a real threat presented itself.. then only to struggle. I get the logic and reasoning behind your point(s), I was just never that person. I want to see the main character slay, unhindered.

About the "everything looks like a nail" - thing: it could be cool to have the protagonist use his one signature spell for everything, but his opponents getting wind of it so in the gravity example the 3rd time they find a way to tether themsekves to the ground - and then the protagonist has a problem cause he's used to gravity working...