Hi-Point carbines are affordable and pretty decent quality. They have some level of customizability, if that's something you're into, though it's mostly proprietary accessories.
In my state you don't have to have a permit to purchase. They kind of exist in that grey realm between a rifle and 'assault weapon'. Plus, they're chambered in pistol calibers. Standard mag is 10, iirc, but you can get 20-rd magazines if that's still available in your neck of the woods.
You can get them in 9mm or 45 acp. I recommend 9 for availability/affordability or 45 for 'stopping power'.
I'm about where you are, except I haven't yet started applying. Sucks that that's what I have to look forward to.