One thing to look out for (mentioned here: https://itch.io/t/2551434/a500-mini-guide )
"If you press MENU to change the games settings in the menu, the A500 Mini will modify the uae file, undoing some of the performance improvements and degrading the experience."
It is possible you inadvertently modified some joypad settings here too. Although I can't say for sure if that was the problem.Anyway, I'm happy you've got it working and that you are enjoying the game!