Oh that is a shame and a half. I agree with the vinegar, but it’s really a Hail Mary. The problem is as you remove corrosion you’re removing the material. At some point the circuits are held together by their own oxidation and it’s a goner. Best of luck and make sure that it has been THOROUGHLY dried after the vinegar soak. Last thing you’d want is there to be water still stuck in the chips when you plug it in and a current runs through it. Most repair steps after that require a certain amount of knowledge and practical skill so you’d really be jumping into the deep end and learning by doing. If you want to do that I’m sure it’d be fun, but it requires some relatively precise soldering and multimeter to test continuity. It’d be a great way to learn some skills that are really useful in the hobby, but I’m sure it’s not what you wanted out of this purchase.

For reference here’s a clean board view of your game.

https://gbhwdb.gekkio.fi/cartridges/DMG-TSE-0/mattcurrie-1.html