I use VLANs to segregate my WiFi traffic and VPN; I have a VLAN for my private WiFi, a VLAN for my guest WiFi, a VLAN for my VPN, and my wired LAN is untagged. All of it plugs into a cheapo unmanaged D-Link gigabit switch, which passes it just fine. All of this goes out over my LAN port (assigned as such).
The APs are VLAN-aware (and tag and filter the appropriate packets) and of course pfSense is VLAN-aware on the other end. Sure I might be able to do some magic configuration on one of my wired ethernet systems to be able to touch VLAN-tagged traffic, but given that there are only ethernet ports in the office and bedrooms, if a bad actor has access to my wired LAN, I have bigger problems than them picking up stuff off the VLANs.
In the meantime, any communication between those three segments (Guest WiFi, Private WiFi, LAN) is at the pleasure of my firewall rules -- which is to say guest WiFi can't see while the others are, by and large, unfettered (though there are some restrictions on VPN).