Which patch version do you use? 1.21?
Wurst runs war3.exe because 1.26 users reported Frozen Throne.exe being extra slow which was an issue for them.
I know several 1.28 and 1.26 developers and vscode run works totally fine.
So it's a problem on your side and you need to provide some more information...
As a quick fix you can try renaming your "Frozen Throne.exe" to war3.exe