Just wanted to comment here also, in case someone finds this thread… There is more info in this thread: FP4: Caller ID "unknown" after last update of /e/OS (2.7-u) on Fairphone 4 - #21 by fpu
Unfortunately I can’t register to gitlab.e.foundation (“Email is not allowed for sign-up. Please use your regular email address. Check with your administrator” - for all my email addresses… go figure), otherwise here is the issue that you opened: Losing network all the time (#8491) · Issues · e / Backlog · GitLab - if I figure out how to register I’ll put a +1 there too.
The solution that works for me is - changing the phone and OS. :-/