There are plenty of desktop music players on Mac that support flac, audacious, Cog, colibri, vox, Plexamp come to mind and there are others including commercial offerings. That is not the issue. People that wish to use the Apple official music ecosystem are SOL.

On the second point, ALAC works just as well as FLAC in that regard.

Yeah there are options already. Swinsian and Doppler are also pretty good. But I think there's still room for improvement.

While I am personally not happy with any of the offerings on MacOS, alternatives don’t help those interested in wanting to use Apple Music with any lossless archive other than ALAC.

> I'm working on a desktop music player for Mac that does support flac

There's already a whole bunch of them

Yes but I think there is room for improvement.

Audacious would be almost perfect if it supported ReplayGain for .m4a