I have much of what you describe: 3 listening environments between near field computer speaker setup, reasonably high end home stereo and dac/amp with high end iems.
I have tried multiple times to discern flac vs 320 mp3 across genres. Every time I believe I can figure it out and I consistently fail to exceed 50% (pure chance) accuracy.
Makes me wonder what ultra-linear source gear or speakers would highlight the differences in real-world situations, if at all. But for my purposes I’ll happily accept the roughly 80% file size reduction for no audible difference.
I could hear the difference between 320 Kbps MP3 and lossless WAV in blind tests in my early 20s - though I needed headphones to do it, and it had to be a track I knew well, and I couldn't tell which was which. They were just different, and neither felt worse. This quickly converted me to using CBR 320 Kbps MP3 for everything, on the basis that it would be just as good as the original.
A couple of years later I found an ambient track that sounded messy at 320 Kbps, and that converted me to using flac instead. Disk space had got cheaper enough over that period that it made no meaningful difference.
THis was all years ago now (I'm in my 40s...), and I don't worry about it too much any more. Firstly, I still use flac, so it's identical to the original anyway. And secondly, even if I did use mp3, my aged ears probably couldn't tell the difference even if I turned the volume up to unreasonable levels.
I think you need to spend more time with the systems and the music you have. Because, at least for me, understanding the differences at the first shot is very unlikely.
Brain is interested in the low hanging fruit, i.e. the music and the melody itself, first. The music needs to became mundane or ordinary to be able to listen it deeper for more details. This is when differences can be heard more easily.
Lastly, you don't need perfect systems to hear differences, but understand how your systems respond to the music you're listening to. i.e., your music system's sound needs to be mundane to your brain too to be able to go from low hanging fruit to minute differences you were not able to hear before.
I have tried multiple times to discern flac vs 320 mp3 across genres. Every time I believe I can figure it out and I consistently fail to exceed 50% (pure chance) accuracy.
Makes me wonder what ultra-linear source gear or speakers would highlight the differences in real-world situations, if at all. But for my purposes I’ll happily accept the roughly 80% file size reduction for no audible difference.