Here are my findings about the difference between the Fiio M11 (returned it due to an issue I got) and the Ibasso DX160 (2020 version).
Moondrop Blessing 2 : sounds warmer and less analytical, making it more enjoyable for me.
Tin Hifi P1 : removes the occassional slight treble peaks (No Treble “peakiness” from 9 to 10)
Shuoer Tape (oratory1990 EQ Preset) : …somehow it has a more natural timbre??? (Timbre from 5 to 6)
Urbanfun ISS014 : polished away some very tiny treble peaks (No Treble “peakiness” from 7 to 8)
Sony XBA-A2 : Tighter bass, bigger soundstage in depth and width (Bass tightness from 5 to 6)
Final Audio E5000 (high gain) : tighter bass and a bit faster bass, which I like (matches really well with the DX160) (Bass tightness from 3 to 5, Bass speed from 2 to 3)
Blon Bl-03 : soundstage is deeper (Soundstage from 5 to 6).
LZ A6 (pink filter) : soundstage is deeper.Timbre is a bit more natural (most likely because the treble extension isnt as good as on the M11 and that is where the Piezo drivers are working in)
Shozy Form 1.1 : Soundstage bigger in depth and width. A bit tighter bass (matches well with the DX160) (Soundstage from 5 to 6)
Final Audio E3000 (high gain) : Soundstage bigger in depth and width. A bit tighter bass (matches well with the DX160) ( Bass tightness from 4 to 5)
Moondrop KXXS : Less analytical sounding, bigger soundstage in depth and widht, tighter bass, less treble peaks. (rank up from B to B+)
Audiosense T800 (stock + brown knowles filter) : NO HISSING! Bigger soundstage
ThieAudio Voyager 3 : reduces hissing, but still a tiny bit left
Azla Azel : Tighter bass, bigger soundstage in depth and width (matches well with the DX160) (rank up from C+ to B)
TFZ No.3 : Tighter bass, bigger soundstage in depth and width (matches well with the DX160) (rank up from C to C+)
Final Audio E1000 : Tighter bass, bigger soundstage in depth and widht but reduced clarity in the treble that makes the overall SQ a bit lower (Rank down from C+ to C)
Tin Hifi T3 : Reduced details, which was its biggest selling point and still sounds unnatural (rank down from C to C-)
Overall : the DX160 makes the sound warmer, tighter bass, less treble peaks (although at the cost of treble extension), with a bigger soundstage (especially in depth) and more fun sounding. While removing the analytical nature of the M11 but it loses out some details due to that, especially in the treble.
I think that the reason why I think the timbre sounds better in the LZ A6 and the Shuoer Tape is because the lesser treble extension makes it so that their drivers (magnetostat in the tape and Piezo in the A6) dont “work” as much as before.