Can't access internet when connecting to VPN from same network

I have a slate plus set up as a VPN server using wireguard.
The slate is connected to a main router through ethernet.

I am able to access the internet through the VPN if I am connecting from outside of my network (ex. when connecting to the VPN from my phone using data).
However, if my phone is connected to the main wifi network, and the VPN is still connected, I cannot access the internet.

Is this expected? I don’t want to have to keep disconnecting from the VPN every time I come home.

I think it may be an expected NAT loop issue. When you’re at home, do you connect to Slate’s Wi-Fi or the main router’s Wi-Fi?

I am connecting through the main router.

Is this something that is limited by the main router? is there something I can do to make this work?

I use a Slate ax as the main router, which doesn’t have that issue because the OpenWRT port forward rule enables reflection by default.

Please check if your main router has that option.