The point of the opnsense is that I can tinker with it without risking our home wifi. It needs to stay up for my wife, for our mqtt devices/home assistant etc.

I don’t introduce points of failure to our home network which is the critical part. If something in the opnsense misbehaves, it only impacts my lab stuff. The FritzBox + Pihole combination has proven pretty stable over years, even though I’m considering getting a second Pihole device for high availability.