Eufy on Network without Internet - Can I see Video on other VLAN?

Hello everyone,

I have my eufy 2k Wifi Doorbell on my Network of Things Network (NoT) that has no access to the internet.

If I enter that network with my phone or PC, I can see the live Video from the Camera.

But if I connect to the main network I cannot, even though the networks are created in a way that when in the main network you can access all networks, but not the other way round.

Is there a way to do this?

I am thinking port forwarding might do the trip but I am not sure what I should do.