I've been unlocking new games and leveling up, a windows says that i have unlocked several maps and I can use diplomacy cards in custom games, but, I have access to just 6 maps and reinforcements cards.

I'm currently level 8 and nothing has changed in the custom level maker.

I have an old game account and it seems It got reset or something like that.

Change the category at the top to "All maps" and click Apply.

It also fixed the new cards available, thank you.