Forza Horizon 4 bugs

My younger brother has a problem with Forza Horizon 4. His problem is that sometimes the game just doesn't save and he is forced to repeat actions that he had already done. The information about game not saving his progress was mostly appeared when
he was changing paint of his cars. The other problem was that his game suddenly crashed, mostly after race. We also couldn't play together, beacuse when he was starting a race, he could drive normally and I was already loading to race and after few seconds
I got the messeage that the event was cancelled and he got messeage that I left convoy. When he wanted to join my convoy, he started joining my session, but he got information that he is supposed to return to freeroam, but when he returned nothing was happening,
the messeage was still apearing and he couldn't do anything about it but leaving. He tried reinstalling game few times, reseting game in application settings in Windows, then reinstalling Xbox App. After reinstalling Xbox App he installed Forza again and was
asked to sync his game to cloud or local files, but after starting both nothing happened. Syncing was going normally and after few minutes messeage about unsuccessful syncing appeared and he could open game or try again. He tried again few more times but nothing
changed, so he decided to open game. Everything was fine, expect that we still couldn't play together and he hadn't paint on any of his few hundreds of cars. All upgrades and progress was unaffected.

:)