UniFi Gateways (not the Cloudy type that have a Network controller baked in) really want to be brought into the collective from the 192.168.1.x subnet. But maybe you've tinkered with the Default untagged VLAN1 network because 192.168.1.x is sooo pedestrian. Maybe you prefer the business-like attitude of 10.x.x.x, or the hipster vibes of 172.23.42.x. Whatever your reasons, here's what help I can offer when the time comes to change out your gateway.
- Prepare yourself (and your family/housemates) emotionally and spiritually for network fuckery.
- Work from a wired host.
- If at all possible, dual-home your UniFi Network app for its current subnet and for 192.168.1.x.