My advice was based on a report from one of the users I support in an Enterprise environment. They said they tried manual removal, and that didn't work, but then tried the Webex tool, and that fixed it.
I've also heard that the browser plugin works, if you don't mind using your browser as a Webex client.
I never upgrade production computers until I'm confident all our critical software works. (I don't block my users from upgrading, but I warn them that if things break, I'll "fix" them by wiping their hard drive and reinstalling Catalina.)
I strongly recommend against upgrading in the first 30 days of a major new OS release.