We learned this one the hard way.
The domain for our own facility services company was registered through a website builder. When we decided to move on, keeping the domain meant settling the account and paying to stay while we sorted it out. A lot of small businesses are in the same spot and don't find out until they try to leave.
So every domain we register goes in your name, in an account you control. We work through access you grant and can take back. If you ever want to leave, you already have everything.