I haven’t been able to properly build a project in UE5EA yet from VS so I haven’t tested this at all. I haven’t read about or seen talk about it in a video. Lots of info out there so I might have missed it.
Currently to support C++17 in UE4 you need to build the engine from source with C++17 support and use VS 2019. UE5 uses VS2019 already which is awesome. Supporting C++17 is the only reason I currently use the source build and I would much prefer to return to using the engine releases on the Epic Launcher.