Helvetica Neue system font in Catalina causing clashes with Adobe Helvetica Neue

The only way to remove fonts installed by the OS in Catalina is to boot to another OS, then remove the unwanted/unneeded fonts from the non-startup drive.

Well, I think you can do it from Terminal, but I haven't tested that yet. And that depends on how old your Mac is.

Older Macs can do a Single User mode startup (Command+S) where you simply end up at a Unix command line. From there, if you know how, you can navigate to any drive and folder, and delete anything.

If you attempt a Single User user mode startup on newer Macs with the security chip, it looks the same to start with (lots of white text on black background scrolling by). But when it gets to the point where you would have the Unix command line, the Mac simply drops to the desktop of the designated startup drive. The closest you can get to Single User on these Macs is a Recovery Mode start and run Terminal from there.

You don't have to boot to another Catalina drive. It can be any other older OS your Mac supports.

Kurt Lang will probably have more direct help for you when he sees this, but here is his website with information on managing Fonts in macOS. http://www.jklstudios.com/misc/osxfonts.html