In general it is simple, make the game more complex + add random factors.

For now it is a bot game, and i see no reason why this would change.

The most simple thing would be to "disvalue" low-effort bots with an additional layer of complexity.

With this change in place, it could also remove the general MMR system and use the cards for access.

Why wasting time in lower leagues with higher level cards?

You match the cards, you can join the league.