Ok, seems like the problem is solved.
These uncommited changes were already applied to the local branch, but the git apply error wasn't very informative.

Thanks!

The uncommitted changes are in git diff format - can't you simply take them and use them with the git command?

Nope. It gives me errors.
Just like the guy that replied in the thread I linked in my previous reply here.

Adding the flags he added also didn't help

Just found this thread,
https://clearml.slack.com/archives/CTK20V944/p1639037799391000
Will try to follow and see (although it looks the same like what I tried)

Still no good, managed to apply with errors only