Fp4 Randomly reboots since last fairphone update

I would not exclude anything at least and especially after updates strange things happen provider specific, especially with Vodafone Germany
FPs troubleshooter as well mentiones VoLTE and Wifi Calling

I would compare APN settings with the provider settings.
Probably it helps to reset to default using the 3 dots.

Overall just guesses.

Just happened on the FP3