@q
It kinda depends on whether you need the latest Android version being stock or are fine with updating via a custom rom (e.g. LineageOs) but if it's just for testing and maybe the version doesn't even matter I recommend just getting a used one which released in the last 5 years or so.

(I personally never bought a new Android phone even as my main one but I always run custom roms to get updates after the manifacturers stopped support. The modell I'm using right now is 6 years old)