Python 3.8.0 Setup Failed - 0x80070666 Another version of this product is already installed / No Python installation detected

I installed 3.8.7, the dependencies didn't match up with the project I was trying so I uninstalled 3.8.7 and wanted to try 3.8.0. I get this error every time.

Things I've tried:

• Using Windows "Remove apps and programs". Doing this results in an error "No python 3.8 installation was found", an incredibly frustrating contradiction.
• Trying everything from this thread, including removing environment variable paths, deleting registry \SOFTWARE\Python\PythonCore3.8 (it was only there for HKEY_CURRENT_USER and wasn't there for HKEY_LOCAL_MACHINE)
• Tried uninstalling 3.8.7 with my 3.8.7 installation .exe, which brings up a "Modify Setup" screen (so it recognizes an installation somehow), but clicking uninstall brings up an error "No Python 3.8 installation was detected." I also tried the "Repair" option, which gives the same error. Choosing the "Modify" option shows me where another installation was (on my OS hard drive) that I deleted, and then ultimately going through with the modify process resulted in the same error as the other two options.

Every time I run a Python uninstallation it recreates the registry keys and the folders, but in the OS drive where none of my installations are. I can't direct the uninstallation program to uninstall from another path.

I'm thinking it's a combination of choosing my own installation paths (which is almost always never worth the trouble it causes) and the fact that my Python paths are not on my OS drive.