Metadata is lost during FLAC to WAV conversion primarily because FLAC uses a modern, standardized tagging system (Vorbis comments) while WAV relies on older, less consistent structures (RIFF INFO chunks or ID3 tags). Many converters fail to map the extensive FLAC tags to the limited WAV structure, or the converter defaults to stripping them, focusing only on audio data
Im not familiar with JRiver, I just use plain old vanilla Media Center. You can restore that metadata information manually, I assume, but I am not an Apple guy either.
I am surprised that your car reads 200GB, I thought cars max out at 30GB but I guess not. Perhaps car manufacturer specific.
Yeah, I use USB storage to play, I do not dongle a player. I meant to say Ford Maverick (last year model), not Chevy, does not include the means to play the files from USB, and I assume will require an external player to do so, but that I cannot confirm. It was the first model car that I drove that I noticed the change/migrations from USB type A to USB type C. The new Maverick has one of each (A &C), but USB A does not recognize or play music.
And to be clear, I do not see data that contends the music is playing at 192/24 (although I have not really searched for it) but judging from the sound, it is definitely hi-resolution sound. I drive older Chevy's a lot (3-5 years old) and while they play music and have fairly good players/choices, the sound is probably not 192/24 but a lower 48 or 96 resolution.

