[2020] Question: Switching to Steam with an old account already linked

So I own the game with FO 1st on the bethesda launcher and I was thinking about moving to Steam. I know the subscribtion doesn't carry over and I'd have to cancel and resub on Steam. The issue is that I already have an old account linked to my steam on which I got some of the creation club items for Fallout 4. If I unlink the old account from Steam would I permanently lose access to the creation club items? And what about the atoms on the bethesda account? Can I still use the beth launcher later on to spend them?