Queries regarding private service connect implementation

Regarding the private service connect, please respond to below questons

1. When using the PSC endpoint mode, in the diagram in GCP documentation. a load balancer is present besides the service attachment at producer end. However, i tried and created a cloud sql PSC endpoint implementation and accessed without creating a load balancer at producer end.is the load balancer an optional thing at the producer end where the service is present.

2. Same is with PSC subnet for Source Nat translation. Are these components optional?.They should have mentioned it explicitly in the documentation

3. How do we get the service attachment URI for "oracle database @ google cloud" managed installation (if anyone has done it earlier)