There should be options for board members to change their names and/or delete their accounts and posts without admin approval. Because of current lack of options, I will not be likely to use these boards in the future nor recommend them to others.

Two of these can be allowed by administrators.
Already available, ACP > Advanced ACP > Users and Groups > Users > Users' permissions > Profile > Can change username
Similarly can be set via Permissions > Forum based permissions.

If however you are referring to your other post unfortunately that is the world of the internet. A lesson hard learned maybe however nowadays you need to think long & hard about anything you place on the internet particularly any personal details which maybe could identify you as even if the options you desire are made available there are always methods of seeing historic information, not peculiar to phpBB, but to any website generally.