I apologize for the late answer.
1.) Yes, VM backups will also be affected. Whichever Gateway you select, that proxy server will be used to send backup data to the VDC Vault.
2.) Yes, it's possible. There’s no special guide, just create a new repository and point it to another "folder". Or create a new Vault and use it as your Agent repository.
Please note, you can't move "Managed by Veeam Agent" backups from one Object Storage to another Object Storage repository. You will need to start new backup chains in the new repository.
Best,Before you perform the move operation, consider the following limitations:
[For Veeam Agent backup policies] You cannot move backups to/from/between object storage repositories.
Fabian