You must create br-vlan in interfaces. Then you create br-vlan123 for each vlan. The same goes for lan but you need to use . Example “lan.123”.
IPv6 fix that got my iPad to stop losing internet. Clear out the IPv6 prefix ula. You can find it under the interface tab. Then go to global network options. This is only needed if you have a firewall in front of the wireless ap.
It doesn’t hurt to disable dhcp and dns services. This is documented in the ap wiki for devices.
This is the settings for a Unifi 6 lite that got it working under 23.03.3 with full speed. My firewall is a Netgate 6100 or pfsense firewall.