How to setup virtual services and shared gateway

I am trying to setup service mesh for 2 different applications running in 2 different namespaces.

NS1: app1 + virtual service
NS2: app2 + virtual service
NS3: shared gateway for app1 and app2 + tls secret

I am not belonging to the infrastructre team, so I dont know all the aspects w.r.t to istio components. I just can tell that in our environment we are used to annotate the namespaces accordingly ( and in order to let istio create the service mesh control plane. Till now I was working with dedicated setup, which means I had dedicated gateway within each app namespace. After annotating app namespaces the control plane shows up and and the deployment of gateway and virtual service produced ingess gateway pods and proper routes in the control plane.

Now, since I am trying to use shared gateway and after creation of virtual service and gateway I miss the route which expect in the app1 and app2 control planes.

Can anybody think of what I am doing wrong ?