Built-in WiFi should support Bridge to VLAN
The XG105w (wireless enabled) only supports Bridge to AP or Separate Zone, and not bridge to VLAN. This is fine for when you a have a really small deployment, which is not integrated with additional Sophos AP's within the environment. For a growing and secure wireless SMB environment the best practice would be to utilise VLAN's and segment the different wireless traffic through the network.
Ideally this config should flow and replicated through AP groups including the XG on-board wireless.
Thank you for reaching out and providing your inputs.
We have added your request to the Backlog . However, we would recommend using Access-points (AP55/AP100) for a growing SMB .