Other users and shared taking up to much space.

Hello! If you are on an account that is sharing iCloud storage you might have to have the main account owner increase the storage plan for the account. You could also reach out to the other user on the account to see if they can adjust their backup settings to free up some space.

Below I have provided some links with more information about iCloud storage and Family Sharing:

Manage your iCloud storage - Apple Support

Share iCloud+ with your family - Apple Support

Is this regarding the storage on your boot drive or iCloud storage?

"Other Users" can be other macOS user accounts on that boot drive. I have seen reports that "Other Users" can refer to other hidden storage used by the system....macOS hasn't been very good at properly delineating the various storage items for the past few years. I have heard that the Spotlight Index may have something to do with it as well.

If the "Other Users" ends up being system data, then sooner or later that storage will be released for use by you. Many times data can be hidden in APFS snapshots which is usually utilized by Time Machine and other backup apps. These snapshots will typically be deleted automatically anywhere from a day to a week, although some apps may mark a snapshot to stick around longer. You can view & delete APFS snapshots by using the information in this Apple article (be careful though because you may affect your backups if the snapshot has not been transferred to external media).

View APFS snapshots in Disk Utility on Mac - Apple Support

I think sometimes iPad & iPhone backups can be hidden as well or if they have their own category in Storage Management.