Use Disk Utility to try to rename it. See if you can rename the Volume Group for that installation assuming you created a separate Container (aka partition) for it. macOS doesn't do well with renaming macOS boot volumes since the macOS boot volumes for macOS 10.15+ consist of a read-only system volume named "Macintosh HD" by default and a data volume for the home User folders called "Macintosh HD - Data" or with some later versions of macOS it may not be just "Data". Rename the main part of the volume name, but make sure to keep " - Data" part of any name intact. I honestly don't know if it is still possible to rename the read-only system volume since it is a signed & sealed volume beginning with macOS 11.x+.
Apple used to keep a hidden file on the boot volume which contained the name to be used for the Option Boot menu, but I don't know where this file is located for macOS 11.x+.
Before you make any attempts, make sure to have a good backup just in case something goes wrong.
These days I make sure to give the macOS boot volume the name I want to see when I erase the drive prior to installing macOS 11.x+ because it is just so hard to make the change later on.
Edit: If you cannot rename the Volume Group, then rename both of the APFS volumes for that installation....sounds like one of them has already been renamed.