Having current issue with this problem.
I have VStudio 2022 and this error appears when following the tutorial for the DodgeTheCreeps
Unable to find package Godot.NET.Sdk. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packages
The previous tutorial on the docs which was the balls and red beams worked. Now when attempting to build, this does not work. I've installed the older SDK 3.4.1 along with re-installing Mono and none of these solutions found online work for this problem.
Godot version 3.4.1
Ironically when following the docs the previous project with the balls and red ramps worked. I've made no changes other than what was mention above and having my external editor open in VSCodium.