If it is just a customised member area, then you could just use Wix existing member profile tutorial.
https://support.wix.com/en/article/corvid-tutorial-building-your-own-members-area
Works fine with the custom signup form collecting whatever user inputs you want and then when the user is manually approved as a site member, the user inputs get saved into the Members dataset from the Wix tutorial above and they will be displayed on the members profile page when they first view it.
Then they can simply edit, change or add anything to the user inputs that you add to that page yourself.