Windows Explorer shows three users and three sets of top level folders

Desktop: Windows 10 Prof version 2004 (OS build 19041.572)
Laptop: Windows 10 Prof version 1903 (OS build 18362.1139 (LG Gram 2018 i7 with a 1 T NVMe drive and 16 GB ram both of
which I installed).

I have three users on my desktop: they all have my name and they are all Administrator; they also have the same photo I created originally on my desktop. All have the same outlook.com email I had to create at some point. I never use it but it is active if I wanted to.

I have one user on my laptop with the same picture and email address as on the desktop. This user is also Administrator.
Since I only have two Windows devices I don't know why three of the same administrators are shown on my desktop. The only thing I can imagine is that it's the result of a major Windows disaster on my laptop when it was quite new. The laptop completely froze in the middle of a windows update and no longer knew I was the owner, no longer knew I'd upgraded from Home to Professional and many other problems. In a fury I brought it to the Microsoft store essentially saying your update broke this brand new computer -- you fix it! They did fix it but they did it their way and no effort was made to clean up everything they left behind.

One day I wasn't paying attention and somehow allowed my desktop windows to sync with my laptop. As a result both share the same Admin along with a third on the desktop whom I've never met :)

I did find the setting to turn off sync and it is now turned off on both computers. But I still have three of the same person and email Admins listed on my desktop. One of them is probably the laptop but why a third?

In Windows Explorer on the desktop AND on the laptop I have two complete sets of Desktop, documents, downloads, favorites etc, AND AFTER these two complete sets I have This PC, desktop, downloads etc. which accurately reflect what is on the disk of that computer. Sometimes I can't find a file because it's in one of the other subsets of folders.
I don't understand any reason to sync Windows on the two computers. Is this correct? I do sync most of Chrome and Google Keep - but I think these are the only things it seems to me that I'll benefit from syncing.

Is there any way to figure out which of the three Admins on my desktop doesn't belong there and remove it without causing chaos on the laptop?

Also, why do I have two extra copies of all the folders (desktop, documents etc) on both computers? Might there be some way to fix this?

I like to run a reasonably clean, logical and organized computer. This is beginning to drive me crazy and I'm also concerned that it may provide some open back door.

Would greatly appreciate your suggestions and help. Thanks.