We just found a better solution to this issue. In the next release (2021.4.11) we will internally constraint the used MSBuild version to a maximum of 17.2. So even if one has VS 17.3 installed, as long as the Microsoft Build Tools 2019 can be found all should be good.
Note that if the above workaround had been applied already, one needs to un-apply it - simply delete the whole package folder and let the build system re-install it.