I had the same error message but the unknown component was MSIX in WinUI 3. Well, MSIX is VS development so I added that component. That didn't do it completely. I had installed Windows App SDK previously. I went into the VS Installer and it wasn't checked under individual components so I checked that. Then I had to change Configuration Manager so Deploy was checked. Then it worked. Hope it helps someone.
The tooling on WinUI is a bit raw right now. Hopefully, it gets fixed soon. Love it other than that.