inaccurate system storage stats in iCloud and elsewhere?

This is making me nuts. I'm saving everything in the iCloud. Optimize is set. I spent a few days getting old documents and such deleted. The system data actually went down from 125gb to about 42gb. It's back up to 116gb. The Total storage used, however, is actually appearing to "sort of" indicating a lot of the files I've deleted recently. I was up to "you're running out of space" messages for the HD even though supposedly EVERYTHING (photos, documents, etc) is in the iCloud.

However, another attempt at figuring this out reveals this. Now, even though I made "As" in school in Math, just looking at these four screens show why I'm losing what's left of my hair.

The Storage screen shows the iCloud Drive with 38GB being used.

The screen capture of the iCloud Drive by Clicking the (i) states that files and folders kept offline are using 8.54GB.

The screen capture of just the iMovie files shows one at 46GB by itself.

We pay for 2TB of storage in the iCloud. We have two computers, a laptop and a MacMini. Both are 500gb (more or less, I understand they're not). I have everything optimized. When I click on the Family plan

(screen capture #4) A totally different set of numbers, closely resembling the first that shows HD storage near the same number ... but note the iCloud Drive is showing 259GB which makes more sense. However, here's the kicker. The Family iCloud amount shows 24GB and it should be at least 250GB or more ...

What numbers am I supposed to believe? And when I get messages "your running out of space, delete something" and I assume all the files and folders etc are in the iCloud. Where are they?

[Edited by Moderator]