Hi belugam,
Welcome to the Apple Community, where some of us do our best to help each other :)
Wondering if your deleted files are in the trash, and will not show up until you empty the trash, and "Restart" your Mac.
Most accurate place to check for amount of storage is always:
Apple icon in top menu > About this Mac > Storage (tab in Top Menu)
Apple support have a useful article online:
How to free up storage space on your Mac
https://support.apple.com/en-us/HT206996
It seems "other" storage is mainly system files etc, that are necessary for smooth operation of your Mac.
Discussion thread with good info on storage, and a link to find more about what “other”storage contains, and:
You might want to scroll to the difference between “free Space” and “available space” from etresoft.
https://discussions.apple.com/thread/252802964?answerId=255420211022&login=true
Some third-party (non-Apple) apps (like Chrome + unnecessary virus-checkers etc) can sometimes consume a large amount of working memory / space.
Backing up old, or large, files you want to keep, eg: Movies, music etc., to an external hard drive, seems a good idea.
Hope this info. is all useful to you :)
