In my sandbox instance, I cannot see the Builder link that by defautl exist next to WorkSpace. I taught it's premissionset issue from super admin restrict access to the community page. So i create new site name "test" and noticed that the Builder link is visible.
But my real need is the Builder link of existing site to access the page to fix the community page task. I tried using by Inserting NetworkId and ProfileId in NetworkMemberGroup object but the insert failed as duplicate error because the networkid and profileid already exists in this object.
I request help from this community the way or step to enable Builder link in this sandbox (I have system admin profile in sandbox) .