Desktop folders move slowly

As you've already been informed of you've installed what is considered by most of the experienced users here as akin to malware: CleanMyMac.

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

So uninstall CMM according to the developer's instructions.

I would suggest the following:

• • Try booting into Safe Mode and see if anything changes.
  • Using their uninstaller, remove the CleanMyMac "helper" you have installed. Anti-virus, "cleaner", and "optimizer" apps cause more problems than they prevent, and simply aren't needed.
  • It appears you have two external drives plugged in. Try ejecting both and see if that changes anything.

The above being said, your Mac is approximately 10 years old...it might be time to consider moving to a new one?

A couple of other suggestions, then:

• • What's the size of these desktop folders that are moving slowly? (Right click-->Get Info will show you their size).
  • Are these folders aliases for folders that reside on a cloud service, or is everything contained on your Mac?
  • You could try creating another Admin user, then booting into it, and see if the issue persists.