I believe that the short tournaments being played should provide experience for the players. This would help increase participation. Perhaps not the same amount of experience as in an official match, but certainly a smaller percentage.

there is youth league where you can give your youth some small exp. This solve the exp a bit.

That's for the younger players, but those who are already 17 or 18 years old and on the senior team generally have very little experience, and right now the only place to gain it is in official tournaments. It's well known that these players are prone to making mistakes if they lack experience, so there must be other opportunities for them to gain that experience.

just let your player play in matches and the penalty get soon moved. Its not for nothing.