It’s possible there’s something wrong with the windows installation, but if it were a missing or corrupt library we would get an error on it most likely. It’s hard to pin down why it believes there’s multiple installs of the plugins while simultaneously being unable to access the files at build time.
Before getting too drastic, I’d see if maybe moving the project to another drive, double checking the plugins installed (and maybe moving them to the project folder again on the new drive and selecting them in engine) to test a couple things out. Are we certain no form of file protection/antivirus could be blocking access to the files? You had mentioned reinstalling VS and it’s components, did the errors change after doing so?