It really depends on what are your expectations and how much time you can dedicate to improve in the game.

If you just wanna farm with brain switched off, monog or monow are the best choices, you just throw your cards on the table and hope the oppo resigns at round 3.

If you are looking to some challenges where you want to outsmart/outplay your oppo, there are other choices like control decks.

I did coaching in the past for both €/fg but probably you can learn slower but free watching streamers, there's plenty.