Backup server to local NAS and Cloud storage
Users are just service accounts to authenticate the MSP360 services on the endpoint with one of your customers. You can only have one user account per endpoint and that account can be shared with all endpoints at a customer. While your main admin account may show up in the Users list, it's really an administration account (see Administrators section) used for management, not for backup.
I do not think you will have an issue changing the storage destination from the User to the Company - by removing from User and then assigning at the Company level, But I am not sure this change provides any benefits. I am going to check with the team and report back on whether this is a good idea. So, hold off on this change until I reply. Thanks.