I've found that Game Boy games are usually not very good.

I bought an Analogue Pocket machine and downloaded an archive of ROMs from archive.org and the only game I've found myself playing from time-to-time is Tetris.

Am I missing out on something? I've tried the Pokemon games but even those seem... well... boring.

PS4 and PS5 have produced the greatest single player games of all time. Nostalgia can be a strong influence.