follow up -
I have created the following setup :

  1. created and connected to an openvpn site (nordvpn)
  2. enabled vpn policies and selected “use vpn for guest”
  3. disabled “use vpn for all processes on the router”
  4. created a policy of type “only allow the following use vpn” for the subnet of the guest network

now when I connect to the main wifi I end up going directly to WAN,
and when connecting to the guest network I go thru VPN.
all this is cool but…

when connected to the non-guest wifi (direct to WAN), I am connected but at a ridiculous rate, to the point where the connection is unusable (sites like youtube barely load and do not play videos).
and when connected to the guest wifi (VPN), everything work fast but obviously via VPN.

ideas?