Run local rsync as normal user and root

I am looking to set up an encrypted backup on an external disk. To do this, I have set up a KDE Vault. Seemingly a restriction of these vaults is that only the user it belongs to can access files inside, and even the root user cannot access it. I would like to use rsync to clone my local disk to this vault. However, if I run rsync as sudo, it is denied permission to copy files. If I do not run it as sudo, it is unable to access some files that require sudo. I would prefer not to disable the security features of the vault or of my filesystem. Is there a way to run rsync such that the source files are accessed by sudo and the destination files are created by my normal user?
Thanks in advance for any advice!
I do not believe my setup details would be relevant here but I will provide them just in case: I am using Arch Linux ARM with KDE Plasma and Wayland.