Is it possible to configure an ESP32 S3 Ethernet PoE as VLAN-aware?

I have a somewhat comparable setup and struggled with the same thing. Short answer: no, there is no vlan support.

I fixed this by setting the port, directly connected to the esphome, to the correct vlan. So the switch is dealing with vlan-stuff. As I have a Unifi network, this was an easy thing to do.