Yes, I believe the biggest problem is That as new manager, you have to face experienced manager. That is fun for a few matches but not for a season.
The solution in My view is:
Put a new manager in a bot league. Max 4 new manager per side. At least 4 bots per side. Lowest division So No risk of relegation!
First season no promotion is allowed! After one full season, one can promote.
Biggest advantage new manager battle other new managers. And battle bots which give easy wins, but nothing encourage more Than winning.
Only in the dark, we succeed!