Do you need album artist tag support? You never mentioned but I thought it might be important.
FYI Fiio M9 and M11 doesn't support it. And if I remember correctly, none of Shanling's do as well.
That's a good observation and fair warning.
(I was also considering a Shanling)
I would never have guessed one of the most basic and essential tags would not be supported by modern players.
I'm now glad I didn't immediately respond to your post, expressing doubts about your statement.
(damn, I gave my overly suspicious mind away now)
Actually that was why I didn't buy M9 in the first place. I was like 95% sure that I was gonna buy it, but then I went to the store and inserted my micro SD card to do a bit of a test, only to find out my entire library was broken into pieces.
Also I should probably mention that the media scan of Fiio M9 was extremely slow.
So I turned around.
Then I got home and found out that the album artist tag support has been requested since 2017 on Fiio's official forum. The X series supported 3rd party apps, but people seemed to prefer to use the stock Fiio Music Player. The buttons on the DAP never worked for 3rd party apps, I guess?http://fiio.me/forum.php?mod=viewthread&tid=42886
A supposedly Fiio guy said in another thread on Jan 2019 that "we will still estimate the feasibility in later firmware update", but so far nothing seems to have happened.http://fiio.me/forum.php?mod=viewthread&tid=43855
It's hard to believe but it seems that most of the Chinese manufacturer (Fiio, Shangling, Hiby...) tend to ignore this feature.
But then again, as far as I am concerned, early iPods were missing album artist tag support as well, up until 4th gen of iPod nano or so.
However FYI Fiio whitelisted some of the music player apps, like Poweramp and doubleTwist, on the latest version of firmware for M series just days ago.
See here: https://www.fiio.com/newsinfo/275335.html
So yes, Fiio M series now kinda support album artist tag.