The BundID is valid nationwide. You do not have to worry about a new account if you move to another federal state.
Questions about BundID

One account for all: BundID on the social platform
With the BundID, you can identify yourself online and submit applications.
Questions about BundID
Unfortunately, the Servicekonto.NRW can no longer be used.
The Servicekonto.NRW can no longer be used on the social platform. Your data and applications will not be automatically transferred to the BundID. Both accounts work independently of each other. To use BundID, you must create your own new account.
Applications that you have submitted via BundID or Servicekonto.NRW are not saved in your personal area. You will only find your draft applications here. Completed applications can be downloaded by you after completing an application together with a processing confirmation.
In principle, it is not necessary to register on the social platform in order to use it. It only makes sense to register with BundID if you want to submit online applications.
You can log in directly when you are asked for authentication during the application process. Or you can register first at BundID.
Your old account will be retained. User accounts that have already been created will not be deleted. However, it is not possible to transfer information and applications.