FCP X Can't open projects since SONOMA 14.1

Hello,

On a Macbook Pro M2 MAX, since I updated to SONOMA 14.1, my final cut 10.6.10 can't open any large projects (by large, I mean longer than 10 minutes, with LUT, Plugin, effect etc..). This is a MAJOR problem for us.

When I try to open one of those project, final cut load forever and I have to kill the app because it is not responding anymore.

Also :

1) I succeeded to delete all the render files, thinking it could help, I also reset the preferences.

2) I can't export the XLM of those libraries containing the projects (same problem on ALL libraries), so I can't try to load this into another library.

3) No problem to load smaller projects like containing only interviews with no effects for instance.

What can I do ?

Many thanks!!!

Emmanuel.