Problems installing Norton 360

You would be better off not installing it. Your Mac currently offers protection without any additional benefit provided by Norton. You will still get fake notifications if you allow a website to send them to you and it also does not stop you from downloading software that brings up Adware. I would suggest you review these posts on this forum:

https://discussions.apple.com/thread/254569992?sortBy=best

https://discussions.apple.com/thread/254790499?sortBy=best

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.  

Unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, public VPNs provide false security from a privacy standpoint.  Read these two articles: Public VPN's are anything but private, Former Malware Distributor Kape Technologies Now Owns a Number of Public VPNs and a Collection of VPN “Review” Websites and Security Risks: The Dangers of Using Free VPNs (eccu.edu)

Feel fortunate that you haven't. been able to install Norton as you now don't have to go thru the effort to uninstall it.