please remove the limit of 3 young teams
add more options for young teams, such as under-15, under-13, women's team (not young, but you get the idea)
one more thing
I don't know what it's like in other countries
but here in Brazil, football schools are very common
they are affiliated to a club, where players can transfer from a football school to a team freely
It is even possible to do this on FM
although
the number of football schools is really large
It's not difficult to find a team with 100 or more of them
Furthermore, they generally have players under 15 years old
generally they (even though they are called a football school) play futsal or 7-a-side football, they have national competitions and everything
I would really like to add something like this but the game's limitations don't allow it