Windows 11, copying files between hard drives painfully slow

I have just retired after 25 years in IT in aerospace. Its so bad especially trying a system restore 90% fails. I thought it was me, seem to re-install so much (murder for relicensing software every build) Its slightly better than NT4 :-). I have started using Tera copy its faster and reliable. I have noticed more and more software having a linux back end. I used to work with Unix years ago and we hardly went down. Software seems to be rushed out these days not a lot of testing before release. Think that's what Sundays are for re-installing windows 11 lol

System Restore corrupting my system was why I reinstalled Win11 in the first place. I am none too pleased with Microsoft right now. I'm retired, and I like playing computer games, otherwise I would just ditch this P.O.S. operating system and use Linux. Copying and pasting files in Linux takes seconds, unlike WinDoze's 19 hour estimate. SMH I am so frustrated and pissed off.

Edit: Problem solved. My system seemed to get worse every time I rebooted. While linux worked at first, that didn't last long. To make a long story short, it turned out that my SATA cable was slowly dying. Used a new SATA cable, and no more problem. My apologies for any disparaging remarks I may have made about Microsoft. haha

Guys, do like I did, I upgraded to Windows 10 and all the problems went away.

Same problem here; mainly with external USB HDD drives. New USB-3 drives with the original drive-specific USB-cable. Only happens on Windows 11; not on Windows 10 (using the same drives). And not only 2.5" and 3.5" HDDs, but also SSDs are affected.

Never found a solution, but there are 2 'reasonable' work-arounds on Windows 11:

1. When it 'gets slow' (i.e. the speed drops/falls significantly, say < 1 MB/s), pause the copy/move statement, wait like 10s and unpause it; that will usually take it back to the regular copy-speed for small files for a while. You possibly need to repeat this step after a certain <random> period. If it doesn't help, try waiter a bit longer, perhaps 15s.
2. Use Total Commander for the file-copies/moves to external drives. Like some of the other tools already mentioned in comments; it uses it's own 'methods' and is not affected (unless you explicitly change these settings) by the weird Win11 Explorer behaviour.

I had the same difficulty, being unable to do the most basic back up because a 30 MB file would take 10 minutes to transfer to an external drive.

Followed someone's advice here and downloaded FastCopy, it works perfectly fine! The transfer is stable at 3.60 MB/s and never plummels down at 0. But you shouldn't have to use a 3rd party software for the most basic copy/paste function.