Finder Info says 932 GB Finder Size column adds up to less than 650 GB threw out over 100GB and still 932

It's (probably) not hidden files. You simply can't believe anything that Finder tells you about storage. It can be wildly incorrect. Plus, at a low level, the APFS file system makes it so that the math doesn't even add up. But even accounting for APFS math, the Finder is in a (fantasy) league of its own when it comes to storage.

You can run the "df -h" command to see the actual amount of free storage. Look at the "Avail" column. That's your free space.

Sadly, elsewhere, Apple recycles the word "Available" to mean something completely different. If you run Disk Utility, you can rely on the "free" value reported for the entire hard drive.

@etresoft is absolutely correct.

Plus there are some areas of the drive that can be inaccessible even with root privileges and Full Disk Access. And some methods of examining the storage on the drive will result in items being counted twice. I was just trying to figure out where all my storage went on one of my personal Macs since the folder I thought should have been using the most storage wasn't even causing much of an impact. No matter how I looked, I always came up a bit short (about 30GB).

As for not gaining any more Free storage space immediately after deleting files, this can be due to two aspects of the APFS file system.

1. Deleted data can still remain behind in hidden APFS snapshots used by Apple's own Time Machine and even third party backup software. At some point (decided by macOS and/or the backup software), those APFS snapshots will automatically be deleted. Once the last APFS snapshot containing the data you deleted is gone, then you will see an increase in the Free storage space.
2. If you copied any items to another location within the same APFS volume, then you did not actually create a second physical copy of that data. You only created a new link to the same physical data. So deleting one of the links will not result in any changes to the Free storage value. You would need to delete all "copies" or links to that data before the data is actually removed. Then you would still be at the mercy of Item#1 with the backup APFS snapshots.

Here is an Apple article with instructions on how to view the APFS snapshots:

View APFS snapshots in Disk Utility on Mac - Apple Support

If you delete the APFS snapshots before they have been completely transferred to external media, then you will be losing the most recent versions of your data, so tread carefully. There is actually a Terminal command that can "thin" APFS snapshots. I'm not sure exactly what it does, perhaps it just tells macOS to delete the snapshots that have already been transferred to external media. If you are using third party backup software, then it may contain settings for how many & how long the snapshots are retained.

As mentioned by @etresoft, the only value of concern is the Free storage value that is shown in Disk Utility (or in the Apple System Profiler). It is a shame that such an important item is hidden away from view and a completely misleading "Available" value is shown every where within macOS.

FYI, here is how the "Free", "Available", and "Purgeable" values are related in case you are interested (and no, you cannot control the "Purgeable" storage....only macOS controls the "Purgeable" storage):

Free space = Available space - Purgeable space

Mindzman wrote:

What bothers me is my computer is slowing down dramatically because 10% of my drive is NOT available.

Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac?

Unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, they provide false security from a privacy standpoint.  Read these articles:  Pubic VPN's are anything but public and Security Risks: The Dangers of Using Free VPNs (eccu.edu).  

Just some food for thought.

Mindzman wrote:

Not a free VPN ExpressVPN had some third party test it. Not sure what you mean by public.

A pubic VPN is one that's not offered by either a bank, business or a school for its members. It's one you download from a public website and install your self.

That should be PUBLIC!🤭🤭