Macintosh - HD Data not showing same space as Macintosh HD

Hi,

I have recently done multiple installations and deletions of OS and now have an issue with the available space.I started deleting photos off my computer, which made space on Macintosh HD, but the GB available on Macintosh - HD Data stays at 18.3, even though when I hover over the available space, it says 34.96 like the amount in Macintosh HD.

For background, the reason I did this was because I was running Catalina and did not have enough space to upgrade to Monterey. I backed everything up to an external drive and thought I erased correctly but I am not knowledgeable at all in partitions, containers, etc., and when I restored using my backup, I think something is wrong.

Do I need to erase both of these again and then reinstall Catalina and then restore my backup? Are they explicitly steps to this? I've read support articles but they are not super clear to me. Thank you.