As for me, I still can't tell the difference, in Chinese, between the sounds of 'shang' and
xiang'.

And 'zhao' and 'jiao'. I am able to create each of these sounds successfully when I speak, but unable to actually distinguish between the sounds when listening.

I have learned to carefully watch the Chinese speakers face; the 'jiao' and 'xiang' sounds result in a widening of the lips in a kind of 'wincing'. The 'zhao and shang' sounds are made with relaxed, unstressed, lips.

After 10 years, I'm still unable to produce a genuine Mandarin 'r' sound as in hot 're' and 'v' sound as in young beautiful woman 'meinv', much to the amusement of my students.