Yes, the router can only be used as an AP.
I have configured mine exactly like this. The rest (routing firewall, DNS, DHCP, etc.) is done by a PC with pfSense. is done by a PC with pfSense.
The router distinguishes between different operation modes:
- Wireless router mode / AiMesh router mode
- Access Point(AP) mode / AiMesh Router in AP mode
- Repeater mode
- Media Bridge
- AiMesh mode

Yes, but would be a bit exaggerated