Android Phone for Learning Python

Heya peeps, good day :)

I've just started picking up Python for the first time and am throughly enjoying every moment of it, it's so mindblowly cool! Been watching a lot of YT of automation/hacking android games and would love to give it a go. Thus would like to pickup a spare android phone to screw around with and learn.

Budget is a soft $250 for 2nd hand, could maybe stretch a bit but don't need the flashest option but also not a piece of junk, happy to pick up cracked screens/dead pixels/whatever cosmetic flaws. A few Qs:

• As there are varying layers of OS atop the hardware as well as the fundamental underlying OS, eg Sumsung's One UI/Xiaomi MIUI/OnePlus' OxygenOS, are the Python commands universal as it'll be interacting with Android itself, or, will I have to learn to deal with each manufacturer's UI in a completely different way?

• Relating to the Q above, is there any difference between Android phones from a dev/tinkerer perspective that I ought to pick one brand/model above others? Those who have messed about with it, what phone are you using?

• Would love to do some penetration testing/exploits of the OS, say I do something that royally messes things up, will I always be able to restore an Android phone back to its factory state by flashing it with the native OS, or is it not that simple?

Any insight/tips/etc would be greatly appreciated, thanks!