CoreDuet stuck in my Trash

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.  

That being said CleanMyMac is considered to be akin to malware by most of the long time contributors to these forums. Uninstall it according to the developer's instructions.

Why did you try to delete those folders originally?

Can you put those items back into the /var/db/ folder? When in the Finder use the Go ➙ Go to Folder… menu option and enter "/var/db/". When the window opens move the two items from the Trash back to their original locations.

FWIW, you may have to disable SIP, delete the folders then re-enable SIP.

Disabling and Enabling System Integrity Protection | Apple Developer Documentation

While in the Finder, try pasting /var/db/ into Finder > Go > Go to Folder…

You're welcome.