Gameboy Pocket wont boot

Hey guys! So I have an old Gameboy Pocket I whipped out for the first time in a while and I plugged the cartridge in. The Nintendo logo appeared fine and the normal ping happened but then the screen would just go blank. I did standard procedure and blew out the cartridge and it still didn't work. I then realised that the contrast wasn't working after the Nintendo logo disappeared from the screen yet it would work when the Nintendo logo would be descending. Help pls?

Notes:

1. Only one game (Tetris Plus), after the Nintendo logo descended, the contrast would work.
2. All the cartridges worked just fine when I plugged them into my GBA SP.
3. There are no bent pins in the Gameboy itself
4. I have a GBC game that when plugged into the GBP, the game logo would pop up and say “Can only be played on GBC” meaning there’s nothing wrong with the cartridge port thingy itself and that the problem is elsewhere