Below photos from the two situations mentioned:
Can you take control of the U23s and then from the side bar > U23s > Tactics > Overview (can't change anything on the tactics screen)
When not in control of U23 training (video attached):
2022-07-29 18-55-07.mkv
Note: This is the same for every skin I have. I've tried switchig the U23 manager, setting tactical training, send more players to the team and nothing wotks