Thinking of upgrading my Mytek Liberty DAC to?

Depends upon how much you are getting out of the system.
Qutest would be worth the effort to demo.
Likely more processing power.
Mytek DACs sound quite good.
Though I can't comment on Glass FX sound.

My suggestion: Element X MQA Streamer+DAC (competes with Mytek Brooklyn Bridge).
https://www.matrix-digi.com/en/products/321.html
Review:
https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-matrix-audio-element-x-dac-streamer-amp.7782/

Hmmm...no other opinions?

What difference do you want to hear?  You're probably not getting a lot of responses because few people are likely to have listened to all of those DACs.  I haven't heard any of them.  If you can describe what you don't like about the Liberty or what you think is missing with it, you may get some recommendations.

Hugo TT2 is high level good ...
Only DAVE offers more ... Low / Mid Definition ...
For < $2000 Qtest is Great!
Wouldn't consider less though ...
TT is Reference level ... that good ...
Ayre may be As ' good ' ... without having done a proper A/B ...
Ayre's gear is exceptional ...
I have not listened to DAVE in a Reference Level System.
Headgear only. (LCD 4z / Qobuz)
TT likely bests all listed ...

 

https://forum.audiogon.com/discussions/driving-gallo-reference-5ls

" Well... I bought the Yggdrasil... because all of the reviews said it one of the top 3 dacs at any price, ranking with the best available. And... though skeptical... I was pleasantly surprised... it is, as they say... "on a whole other level".... cont'd..."