if you want one to show you why a move is good or bad, try decode chess. its free and strong
Well, 2 decodes a day for free... Better than nothing, but they're definitely trying to hook you. ;-)
U Could use Stockfish 18 Chess Engine(The Current Best engine in the world) it is Open Source, free, and u can download it straight from Google Play Store
if you want one to show you why a move is good or bad, try decode chess. its free and strong