Thank you for confirming on private messages that issue is resolved after connecting with you on teams call on Aug 1st itself.
Attached case summary for your reference.
Issue: Not able to save "selected virtual network and public Ip" with private endpoint enabled on private endpoints side
Status - Resolved after adding the needed permission (took some time relay the permission changes probably on backend
Checks done from Support side
Permission:
Configured Search service contributor for User and Language resource
Networking:
Service endpoints configured
Subnet join/read permission to communicate
Custom subdomain enabled on Azure language resource
AI search - Basic tier minimum as needed
Org policy
Nothing found in activity logs to show cause org policy block
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