I definitely respect the dedication to playing on the original hardware. I got a retrostone a few years ago and it’s pretty fun for mobile retro gaming. I’ve got access to all the game boy iterations and NES, SNES and Sega Genesis and it looks kinda like an original game boy.
Replacing a gameboy cartridge battery was the first time I ever soldered anything, and I used one of the cheapest soldering irons I could find in a hardware store. It was definitely not without complications, but I eventually did it correctly. Also not really related but I just wanted to say I absolutely despise that little screw Nintendo used on the cartridges. Seriously, who tf is it supposed to be "secure" from.