@drazraeltod Update! I had this bluetooth gamepad at home (a cute mini 8BitDo Zero 2 https://www.8bitdo.com/zero2/) and if I put it in keyboard mode; evtest catches the events and gives the product/vendor info (not listed in lsusb).
I also got feedback about an utility 'input-remapper' that makes all of the setup easy with a GUI. So it should work with bluetooth keypad as well following the same method. I updated the article.