I can't speak for the more "entreprise-y" unifi stuff but the routing on the ubiquiti gear i've used is actually just FRR and if you SSH in you can do a whole lot more than is surfaced through the UI - for example, I have VXLAN running on my UDR7 right now.
It's not something I've tried but I imagine you could actually expose FRR directly and configure through that
It's not something I've tried but I imagine you could actually expose FRR directly and configure through that