Having similar problem. It took me one week to figure out a way.

Problem: Upgraded a solution (.sln) from VS2017 to VS2022. Got this error (The build tools for v143 (Platform Toolset = 'v143') cannot be found), even though the MSVC v143 has been installed. Tried many approaches without success: recheck $(VCTargetsPath), examine path of Microsoft.CppBuild.targes, reinstall VS2022, choose many alternatives v143 toolsets selections, read content .sln & .vcxproj by Notepad. Hardly to find what is wrong at my machine.

Finally I found a "tricky" steps to let the IDE works ( The Idea is to "restore" the ability of the IDE to "see" the v143)

(1) Remove the Project (where the error come from) (the project is a VC++) from the Solution (do it in Solution Explorer)

(2) Add a new sample VC++ project (ConsoleApplication), set PlatformToolset=v143 for this project

(3) Rebuild solution (it works). Save the solution.

(4) Re-add the original Project, and compile. it works.

(5) Review the new Sample (VC++ project) from the solution, save it.

Hope this can help.