Share FLAC playlists between Mac and iPhone?

[Exophile]

My digital library is mainly in FLAC format (a few MP3s). I play them both on a Mac computer running OS 10.15/Catalina and on Iphone (with Dragonfly cobalt as DAC). I try to find something where I can swap a playlist directly (no cloud nonsense) between Mac and Iphone (both ways), so that I don't have to manually re-create every playlist on every single device. Should also be airplay capable.

What I tried so far:
Desktop:
- PureMusic add on to iTunes, but some files not playing, and does not support airplay.
- VOX: cannot link directly to files, have to go through iTunes, and most FLAC files not playing.

Mobile:
- VOX: but playlists did not play in order, absolutely need that.
- FLACBOX: requires cloud for synchronization, and no desktop version available.

Looking at Audirvana and Roon, but both are desktop only?
Audirvana seems to controllable through mobile device, but essentially as a remote, not as an independent playing device.

Or is there some common playlist format that is cross platform compatible? Something like a .pdf flie, but for playlists? How to swap them between iPhone and Mac desktop?

This really should not be that hard to do, but I cannot find anything. Would very much appreciate any pointers. Happy to pay for it if it actually works. Thanks!

[Dave W]

I use this to sync my Itunes with my Android phone. It may also do what you want, have a look here https://www.jrtstudio.com/iSyncr/Tutorials

[bosa]

I use Jriver on my Mac. Files are on the Mac and/or NAS device.

Jremote on iPhone and iPad can access the files and play on Mac as a remote control or on i device locally as a choice in the remote app.

You pay for Jriver and Jremote separately.