CD/DVD burner does not work with iMac Plus and macOS 11.

The best antivirus, cleaning app, and overall maintenance app for Mac OS is Mac OS itself. All you need to do with Mac OS to keep it secure and running well is to keep it up-to-date and do periodic (about 1x per week) restarts. Other than that, leave it alone. Adding third party antivirus, cleaning, security and other types of maintenance apps to Mac OS adds no additional level of security. The only thing these apps do is have the opposite affect users want. They make Mac OS slow, unstable, generate odd behavior (much like you are experiencing) and make Mac OS appear buggy. 

Please locate the developers uninstall instructions for Kapersky and CleanMyMac and follow to the letter. Then restart in Safe Mode per the directions in Use safe mode to isolate issues with your Mac and then restart normally. 

In support of rkaufmann87's recommendations I offer the following: 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 user tip describes what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community   

Also unless you're using a true VPN tunnel, such as between you and your employer's or bank's servers, they are useless. Public VPN's are anything but private.  

That being said after uninstalling according to the developer's instructions you can check to see if you've removed all of the supporting files by downloading and running Find Any File to search for any files with the application's name  and the developer's name in the file name.  For the software mentioned you'd do the following search(es): 

1 - Name contains cleanmymac

2 - Name contains macpaw

3 - Name contains kaspersky

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

You likely have an iMac as there is no such thing as an iMac Plus. Also, please do the following:

Please navigate to the Mac App Store or navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211

Glad to hear it worked!