Let me guide you on how you can change your Primary User, Admjj.
May I know what issues are you experiencing when changing your Primary User? You can transfer the primary admin role to an existing QuickBooks user. If the person isn't a user, you can add them first as a new user. Then, transfer them to the primary role. To do so, follow the steps outlined below:
In the Role column, make sure they are listed as Admin. If they’re not, select Edit to change their role to admin.
Select the ellipsis ⋮ icon in the Action section. Then, select Change primary admin.
Select Change primary admin again to confirm the change.
Sign out of QuickBooks.
Once the user gets the invitation email, let them select the link and accept the invitation as primary admin. To give you more information about managing users, check out this article for more information: Add, Manage, or Delete Users in QuickBooks Online.