Ronaldo made a very mistake going back to Manchester united when he knew he wasn't ready to retire from professional football. Manchester united weren't getting any better so his move was very surprising. If he knew he couldn't build with them then why did he return. Did he think he's the same Ronaldo of old, surely age wasn't on his side as he can't play at the peak as he usually does and carry the teams all by himself with goal scoring ability.
Cristiano Ronaldo has made a bad relationship with Manchester United after asking him to be sold to another club, as his transfer progressed and none of the teams interested in signing Ronaldo made his decision to stay at Manchester United next season. Moreover, the relationship with Manchester United manager Erik Tan Hag will definitely be difficult for Ronaldo because he really wants to move from Manchester United.
Have missing on several match pre season I think not easy to faced moment right now for Cristiano Ronaldo, but he can get good feedback with Manchester United later if keep stay by giving best performance and always consistent scoring goals. Nowadays if Ronaldo have decision keep stay with Manchester United he need return as soon possible to Manchester United team training and make debut for pre season match.
After Ronaldo stated he wanted to leave Man United and constantly tried to make his wish come true, then this will have an impact on the whole team and of course, the Man United fans. I think there must be someone who is not happy about it, and if Ronaldo continues to play with Man United, it's likely that the team's conditions will become less harmonious. Moreover, Ronaldo's performance will also be questioned, it could be he won't play wholeheartedly because it's clear that his heart is not for Man United anymore.