I have had some network issues since installing the update my Nothing (3a) Pro.
It has been loss of mobile network connectivity both with mobile reception showing and at times showing as not having a network reception.
I am on Wi-Fi most of the time, as I suspect most of us are, so I can’t easily say how often it happens.
Restarting the phone resolves the issue, sometimes with a short delay.
I don’t know if it is actually an issue with the phone or an issue with the mobile network (EE in the UK). If it is the phone, I don’t know if it is a result of the update or another issue.
Hopefully, it will resolve itself.