This reminds me of the 2021 (?) BETA where if you had more than 3 managers, all your teams would be getting injured non stop. I have rotated every teams friendlies with the youth team players and always subbed out at half time.
So far, just before the start of the season:
Mainz: 8
Dortmund: 5
Gladbach: 4
Wolfsburg: 4
Hoffenheim: 4
Bayern: 2
League Average: 3.8