BigSur. Thousands of Duplicate Files on my mac that reappear after deleting locally, on iCloud and emptying trash

I did have some luck by doing:

1) go to iCloud. Com and delete the duplicate files from iCloud.com

1a) I found the duplicates by going to finder type ‘command+f’ then change kind to name. Change marches to ends with or contains then in the entry field enter ‘ 2’ or ‘ 3’ or ‘ 4’ etc. literally space and the number or space number . Then delete from the web iCloud.com. Not the Mac itself.

2) Let the deletions sync to the mac and the backup drive and delete what is need from the trash.

3) Unplug the backup drive

4) Completely delete everything from the mac

5) reinstall the OS

6) only reinstall the data, ie don’t bring apps or settings back

7) manually get all needed apps from App Store or

8) download what you need from the internet

9) get a new backup drive and put backups on the new backup drive.

I still cannot get 1 file out of the trash. It always comes back. I don’t know how to find the trash on iCloud, if the trash is there.

I ended up doing the above except (9) twice.

My machine “seems” OK now other than the unremovable trash item. I can delete the trash item using the terminal, but it always comes back.