Sequoia-Slow-Disk-Utilities(First Aid) failed/+stops; icloud-drive-Copy to USB 3.o very slow/stops.. DT & Doc to ext HD ?????????

I have never experienced any "slow down" with iCloud Drive.

If you don't have multiple devices you need to keep in sync or need to access the files from the Web on another computer, then syncing Desktop & Documents in iCloud Drive is pretty much useless.

I do not share files with anyone else and this mandatory file sharing feature of iCloud-drive

I have no idea what you mean by this statement. I do not share any files with anyone, so it is obviously not mandatory. If you are referring to Desktop & Documents syncing, that is not mandatory, either. You can use iCloud Drive independently of syncing those two folders, or you can not use it at all.

iCloud-drive is too slow for "HOME USERS" to copy files (Desktop & Documents) to a USB 3.0 external WD or Lacie 4TB drive

I'm not sure why I would do that if I had the data synced across all my devices, so I have no idea what the speed should be. My guess it is the connection speed of the external drive. Use System Information to see what protocol it is using. If it says the max speed is 480 mbps, it is connected as USB2. I've seen some hubs revert all ports to USB 2 if there are any USB 2 only devices attached.

Disk Utility fails on several attempts, but finally after repeated tries it starts running, noting errors, etc. , but"Disk Utility" never corrects errors on the internal HD... just keeps noting the errors each time Disk Utility is run. ]

Run First Aid while started up in Recovery. Start at the lowest level, Volumes, then Containers, then the drive itself.

Disk Utility fails on several attempts, but finally after repeated tries it starts running, noting errors, etc. , but"Disk Utility" never corrects errors on the internal HD... just keeps noting the errors each time Disk Utility is run. ]

Often Disk Utility "errors" are just warnings that can be ignored. But continue making Time Machine and preferably also other backups like with Carbon Copy Cloner or Super Duper.

FWIW I recently noticed that when booted to Recovery, Disk Utility issued a warning about a potential bootability problem with my Mac mini 2018 internal disk. But in Internet Recovery the Disk Utility did not issue the same warning so for now I have ignored that. Maybe those Recovery systems use different Disk Utility versions. In the past I have once had a more serious looking Disk Utility error and then I backupped, erased, installed, and restored when doing the next major macOS upgrade so that error was cleared. But maybe that was overreacting.