Security is when the device stops people other than the owner from doing something the owner doesn't want.

This is the opposite. The device is stopping the owner from doing something that someone else doesn't want.

Because when my device stops me, the user, from doing something I want, thats an antifeature. In this case I want to take a screenshot, and the device prevents this.

Just remove the restriction from the app. If you are in control of your phone it isn't hard.

It actually is hard. When I looked in to it the only way to fix the issue was using xposed modules which did not work on my version of android/phone and is a security risk because I now have to load some untrusted module as root so I can get the phone to stop blocking me from what I'm trying to do.

Why don't you just disable the flag in the app which blocks screenshots?

It'd be way easier if I could turn if off device-wide instead of trying to work out how to modify the obfuscated app my bank provides.