Since 10.1... wow!
No wonder there is so much cruft in this system.
You have lots of problematic things in there - remnants from Norton, Avast...
plus many that are too old and do not work, like flash, silverlight....
You have a lot of "Startup Items" - which are not something to be used since Yosemite
You have Chrome - this alone is enough to "kill" FCP.
See https://chromeisbad.com for an explanation
You could follow the instructions in the above site for removing Chrome and its evil keystone helpers, but your hole system - pardon my bluntness - is a mess.
It is high time you do a clean sweep.
Make full backups, preferably two.
Create a Catalina installer on a usb thumb drive.
Boot from the installer, completely erase the internal drive (not just the volumes in it, the full drive).
Install a clean system, then migrate ONLY the user accounts.
Install any applications that you do need.