The Gen V was a stepping stone to the Gen 6. From what I understand, Glock wanted to make new models of all their guns so you can’t put a switch on them, hoping that California would ease restrictions on their guns.
The Gen V was basically a testbed for their new anti-switch design to make sure the gun would still function right. Worked well enough, because internally, the gen V and gen 6 are damn near identical.
Didn’t work out too well, though. The gun functions absolutely fine, but people figured out how to put the switches on them anyway, and California remains unimpressed by Glock’s efforts.
You can get clip extensions on the base 13 mag up to +5 extensions to get to 18+1 in chamber instead of carrying that 27 n throwing off concealment n comfort