VLANs are at layer 2 which is switching. Routing is layer 3. I have several Unifi switches and a controller (running on an rpi) on my network but I use my own

VLANs are at layer 2 which is switching. Routing is layer 3. I have several Unifi switches and a controller (running on an rpi) on my network but I use my own router. I can setup VLAN access ports and trunks all day on the switches no problem, but I can't control the layer 3 routing between those VLANs with the controller, which is what you're talking about. By setting up a gateway/network on each VLAN from my router I can control routing. It's just not as slick as having a USG where it's all controlled via the controller UI.