So, instead of working on the C# project I decided to clean up my dotnet install and remove all obsolete runtimes. Found one that was *somehow* sticking in the SDK list no matter what I did. Spent about an hour trying to figure out how to uninstall .NET 5.0.300 SDK/5.0.6 runtime which was allegedly installed/repaired/uninstalled just fine with the standalone installer, but still kept staying in "dotnet sdk check" list no matter what I did. The "dotnet core uninstall tool" was of no use. Had to go manually clean up the Program Files\dotnet directory. Why did this thing get stuck there? No clue. Why was it quasi-perma-installed? No idea. #JustWindowsThings