I actually end up using my FPGBC more than my backlight-modded GBC these days, it’s just nice to not have to worry about maintaining ~30yr old circuit components lol
Definitely check out makho’s firmware repo https://github.com/makhowastaken/GWGBC_FW and docs if you go this route, using these I get perfect compatibility with all authentic game cartridges (flash carts can be a little iffy, but the point of this device is to play original carts, so imo not a big deal, but worth stating).
Solid plan - since the DMG runs off 6v instead of 3v it’s a better backlight platform anyway if you’re not doing a battery mod (less need to worry about power regulation/battery life).
And DMG kits usually just replace the whole display daughter board, so dead easy install, comparatively.