I do this for a living, and I've done it for myself.
I've moved my own businesses off rented platforms and onto sites I control. I've rescued a site whose owner didn't even know who was hosting it, untangled the domain, the email, the security certificate, the whole mess, and handed back full control.
This isn't theory for me. It's the exact work I do, start to finish. No bloated agency, no junior, no long contract. Just the person who does the migration, getting you free and making sure you own every piece when it's done.