And I also understood correctly that when you buy a subscription for 10€, do you have the opportunity to try beta tests of games? Or the versions that haven't been released yet and my name is in the credits?
The 10$ one is the femdom amazonian tier which means you get access to the newest stable version of the game, for example 0.1.4 since it's the newest stable release. All patreon tiers get their names in the credits. The tier that gets to playtest beta versions is fmg boss.