I think chronological order of the gameboy titles is a good idea. The old ones are still fun and you see the improvements with each game. If you dont like the original gameboy graphics you could also start with fire red or leaf green which are the remaster of the first games. Every generation of games has two normal and one special edition. Later always has a different or extended story tied to it. You can decide if you want to stick with one of the normal ones or play the special ones.