New clear black shell to fit the IPS screen v3 from funny playing (no soldering needed! This is awesome, I can control the screen with just a touch on the GBA logo).
I also added a rechargeable usb c battery, so far it is already lasting 2x longer thanks when I used AA (6 hours in, with a single charge, and medium brightness + sound).
Next steps would probably be:
cleanAmp, because I noticed some kind of white noise with my headphones plugged in
GBA accelerator to replace the stock clock (and make grinding in Pokémon Ruby faster probably)