@robert The issue with your suggestion of setting the profile editing to 10000 posts is that it prevents changing anything in My Profile. It prevents them from entering a website, it prevents them from adding an avatar, it prevents users from adding any biographical About Me information, it prevents them from adding their social media handles and it prevents them from adding a signature.
All I want to do is make the fields I mention Read Only to protect the integrity of the userbase within WordPress and ensure that everything remains exactly the same as originally entered by us.
The setting does its job correctly because the things you've mentioned are also fields of user profiles. That setting is a profile editing controller setting.
If you want to have field level control and individually manage user profile fields you should check the wpForo User Custom Fields addon: https://gvectors.com/product/wpforo-user-custom-fields/
I attached screenshots showing settings that can be managed for each profile fields:
