I bought a Gameboy micro that flickered briefly but didn't stay on. All it needed was a new battery. While I threw away the old battery I'll show you how to replace it to fix your own.
Precision screwdrivers: https://amzn.to/41InFvj
Inexpensive replacement battery: https://amzn.to/4gp2HWR
More expensive battery at: https://retrogamerepairshop.com
GameBoy Micro stand and more at Creality Cloud: https://c.creality.com/zOccNQH
Creality PLA: https://amzn.to/3Z2RDbP
Creality ABS: https://amzn.to/3AGpVrY