Hwy JustRelax2!
Can you open Finder, on the top menu click Go, and while holding the Option key click Library in the drop down menu.
Afterwards, press Command i on the keyboard to get the size of the folder?
If this is the culprit, I do have some suggestions, but keep a Time Machine back up before deleting any data:
In the ~/Library, of the folders, check the size of:
Application Support
Caches
Containers
Group Containers
Logs
Mail
Messages
Mobile Documents
Screen Recordings (If there)
Not all folders are just expendable, but store data or have some essential function for the OS or some other program you have.
If you find a large sized folder above, check:
~/Application Support/MobileSync/Backups, (These are iOS backups, perhaps you have old ones you don’t need anymore and can remove).
~/Caches, (If this folder is large, you can safely delete all the contents, although initially it may slow things down, they will build up again as you use your Mac, but you will not lose any data).
~/Containers/com.apple.mail, (Or Mail), (If this folder is very large, most likely you have Mail logging enabled, and if it’s Mail logs using all your space, you can safely delete them and disable Mail logging to prevent this in the future):
Open the Mail app, On the top menu, select Window > Connection Doctor > Show Logs, once that Finder window opens, hit Command i again to get the size, of it is large, delete all the contents and empty the Trash.
You can them disable Mail logging in the Connection Doctor window by unchecking it.
~/Group Containers, (I’ve found this folder to hold important data, such as Office documents and more third party data, and some local data, if you find this folder to be larger than it should be, let me know).
~/Logs, (These are typically just diagnostic logs and can also be deleted if using too much storage).
~/Mail, (This folder does hold copies of all of your Mail, so is important, all though you may have an IMAP account, and they are safely stored on the server, your Mailboxes “On My Mac” are also here, so also wouldn’t want to delete them without that backup and/ or exporting them first. I have seen certain email providers cause a glitch to where the Mail folder just grows and grows, so you can monitor this folder to see if that’s the case.
~/Messages, (If you use the Messages app, they are stored here). If you don’t need all the Messages on your phone etc. to also be on your Mac, you can delete the contents of this folder. (Make sure if you’re using iCloud for Messages that you disable it and sign out of the Messages app via Messages > Preferences first so your other devices aren’t affected).
~/Screen Recordings. I’ve seen this folder blow up due to third party applications such as video conferencing programs that maybe set to automatically download a copy of every session, so if you don’t need, can delete.
Let me know the results of the folder sizes and will help out if I can. Likewise, if you know you can delete safely, restart them empty the Trash. Likewise, for System folders as the ones mentioned, you would want to delete the files within and not the folders themselves.