Depending on how you've chosen to backup your personal files from user accounts
to an external archive, you may also wish to make sure there are suitable duplicates
that are accessible through conventional methods; such as search by content.
And good Time Machine backups on external purpose-dedicated storage is a start.
Free up storage space on your Mac
Then par the content of the main congestion to manageable levels; a good deal of
the items which appear as "Other" are not in one folder or location; & are automatic
to the generic results. There is no Folder of those items; most are used by System and
are randomly dispersed.
A good backup and then in addition, move your content to an external drive. If the
internal Mac's storage is not internally upgradeable to larger capacity, use an external.
Those can be configured to run the Mac from; & in some cases, maybe not.
And this topic has been exhaustively re-stated; problematic if not approached as it is.