Even if you added a field here were the user who is creating the contact can select who they want to assign the new contact too.

This looks like a duplicate of https://ideas.gohighlevel.com/automations/p/assign-to-user-who-adds-contact and https://ideas.gohighlevel.com/automations/p/automatically-assign-the-contact-when-created-manually

Also, possibly a duplicate of https://ideas.gohighlevel.com/call-tracking/p/auto-assign-contact-to-the-user-that-called-them-first

Also, Default Assign User to a contact they called for the first time!

This should be a feature!