Mar 21 update: TuneBlade casts to devices which emulate the Apple AirPlay; Stream What You Hear (SWYH) casts to DLNA devices. As far as I know Windows 10 uses LPCM for DLNA. I have an Arylic S50 WiFi receiver which supports both AirPlay and DLNA but (small print) doesn't support LPCM, only WAV and MP3. So TuneBlade works for me on Windows, but SWYH doesn't. (With all software as of March 2021, Win10/64.) Both TuneBlade and SWYH stream ALL Windows audio, including system sounds. Foobar2000 can be set up (with a plugin) to cast to the S50; I'm not sure if via AirPlay or DLNA.