Guys i have was facing this issue for an entire day at my work, just now solved by just copy pasting the MSBuild.exe file in C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\Current\Bin to C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\15.0\Bin.
I tried all the suggested methods in this thread none worked. If anyone happened to face this issue straight away use npm install --global --production windows-build-tools --vs2019 or --vs2017 . and copy paste the exe file.