I Built My Own Audio Player

I've been building a music collection in FLAC format for 25 years, and last year I bought an (Android) phone and a MicroSD card of 1TB that fits all of my music. It's been a long project for technology to catch up, but now that it's possible to have all of it in my pocket, I'm pretty happy with it.

I'm sure I can't be the only one that doesn't want to be a renter, give up control and stream anything the industry wants to push or deal with ads. It's cool to see some even go to great lengths to write their own application.

Technology has caught up many years ago, it's just that you insist on an format not fit for purpose. With good reencoding you get transparent audio quality (impossible to hear a difference) to fit all of your music on a much smaller card. (and as a backup you can always have those FLACs on the desktop)

People should use wavpack for archiving instead of flac, to be quite honest. It feels like FLAC has mindshare and name recognition but it doesn't support hybrid encoding (which is great for storing audio for archival and playback) or more than 8 channels of audio.

Music has 2 channels, so that feature is of no use. The other feature is cool as it avoids the need t maintain 2 sets of tags, though as far as I understand, it's not widely supported, especially in smartphones

Music absolutely uses more than two channels. Or less. You don't need special "support" either any more than flac, you just decode it and write the bytes to your output buffer.

How prevalent is music with >8 channels???

And it wasn't "special", it's just apps don't support playing the format

You don't pick an archival format for the common case, you pick it for all cases. But to answer the question, virtually every film soundtrack for the last 10 years.