This can be done on UniFi using policy based routing too trivially if anyone wants to repeat this.
Instructions using the unifi mobile app as it’s what I have to hand:
1) download wireguard conf file from vpn provider. On mobile app settings -> vpn client -> add new -> wireguard. Upload the file and save it
2) settings -> policy engine -> policy based routes. New. Select what to route -> specific traffic. Source = all devices. destination = domain name. Here add any domains you like. Interface = add the vpn you added in step 1
Instructions using the unifi mobile app as it’s what I have to hand:
1) download wireguard conf file from vpn provider. On mobile app settings -> vpn client -> add new -> wireguard. Upload the file and save it
2) settings -> policy engine -> policy based routes. New. Select what to route -> specific traffic. Source = all devices. destination = domain name. Here add any domains you like. Interface = add the vpn you added in step 1