I first created a Premium Site with the Editor. Now I want to ralaunch this in Studio. Wix said, that I cannot switch and I have to rebuild the Site in Studio. So I did, but now I cannot get the Site on to the existing Domain because Wix wants me to create a new Premium Account with the Studio-Site. Can I switch the new Studio-Site to the Premium Account from the Editor-Site somehow?
I have this exact same issue! I’ve just created 2 premium accounts and when I created the initial site, it did it in editor (no option to use studio?) and now I realise I need studio to create what I want.
Having to start from scratch is frustrating, but its still early stages so will grit my teeth and move on. But, like you say, how do I then transfer my domain and premium account over to studio without having to pay for another premium account?
Did you find out how to achieve this?
Hey!
Hopefully I can clear a few things up and point you in the right direction 
For each site in a Wix account (regardless of editor) you’ll need a premium plan to connect a domain and get access to various features.
If you have an existing premium plan, it can be transferred to a different site using the steps outlined here - Wix Studio: Assigning a Wix Premium Plan to a Wix Studio Site | Help Center | Wix.com
And to move assign a domain that is connected to a different site, you can follow these steps here - Assigning a Domain to a Site in Your Wix Account | Help Center | Wix.com
So i have an editor site, and a premium plan that has all of the events, bookings, store, etc… I was told that you cannot move that premium plan to a studio site, even if you create your site as a new site under studio, that they are not migrating those premium plans at all even if you swap it to a studio plan? is that correct?