Fairphone 5 has random reboots - 5GHz the problem?

Recently I got a fairphone 5 - something that has been on my bucket list for a while!
But it’s become a pain to use since it constantly restarts. I’ve heard this can be related to network changes - but I’ve already switched mobile networks from 5g/4g/3g/2g to 4g/3g/2g and the problem still persists.

My home wifi has a 5GHz frequency I believe, could this be the cause my phone keeps crashing when I move around / out of my house?

in general on 5GHz Wifi i don’t have with FP5 problem, but some peoples in this thread have problem if in router (with OpenWrt maybe with stock?) have enabled 802.11r (Fast Transition)