Hi,I agree the bot team fillers is not a good solution for level above 5.
Now i'm at level 16,and after playing a lot of leagues full of illegal and bot teams,last 2 season I've been playing a league
built on all friends of mine.No robot is present and the league is difficult and interesting for everyone.

If you have at least 13 friends of your level each season (a friend who's already in your league,a friend of your level who is promoted like you or a friend of an above level who tanks his season) ,you already have a complete league that can't be divided.

If you have no friends,your quality level may let you be eligible for jumping levels to fill some league.

Try to prevent, as soon as possible