@jga40, running Windows on your Mac using either BC or a virtual system doesn't mean your Mac is threatened by what happens in the Windows side. Even if your windows "system" was hijacked by a virus for Windows, that virus can do nothing to the Mac side of the system. It cannot harm the macOS software or the system there. Even in a virtual system, it cannot get out of the emulator. CleanMyMac is a very aggressive program that has caused a lot of problems for a lot of people because it "cleaned" essential files and created issues as a result. Most of us here recommend that you NOT use CMM. As for the "garbage left behind" on uninstall, that stuff is trivial and harmless. A few plist files, maybe a config file here or there. Small files that you don't need to worry about. If you really want to get rid of them, get AppCleaner and just drag the application to be deleted to the AppCleaner window and it will tidy that up for you, for free.
I ran Win7, then Win10, in a Parallels environment for 10 years to support one application that my wife's business needed. She is retired now, but I keep the Windows around to play some old Windows games in. No A/V software as the system never connects to the Internet from Windows. Works perfectly well, no problems at all.