@Codrinu I haven't heard any of Fezz amps so I can't do a comparison with Envy, for me my Envy Performance is an endgame tube amp, however the thing to remember is that eventually you will like to do tube rolling and if you consider Elrogs this will not be a cheap option either. The one drawback Envy has in my case is that it can not be used with easy to drive IEMs (for IEMs Pro iCan has been good choice for me until it broke).How is the match between MScaler-Hugo tt2 combo and Felix Envy? I wandering if it worth to make this (no little) investment in the future. For the moment I use Fezz Omega Lupi when I want tubes sound.
As for synergy between TT2 or MTT2 and Envy I would say it is very good at least: you don't miss any of TT2 musicality and details, the instrument placement (this could be very headphone dependant just like a sound stage size) and scene width of solo TT2 is retained. Listening straight from TT2 in comparison the music can miss a bit of life and after switching back from Envy straight to TT2 you can have a feeling the TT2 sounds a bit brighter (or a bit sterile, but keep in mind that TT2 does not sound sterile on its own, its just a feeling after you compare both side by side).
Another key factor is that I prefer Rockna Wavelight over Mscaled TT2, and if you consider WaveLight with WaveLight Server as upsampler the winner is Rockna again. The difference between Rockna and MTT2 is that I could listen to WaveLight (without any upsampling) for whole day (and in fact I do it) without feeling any fatigue while listening to MTT2 always makes me tired at some point.
If you plan or have Susvara, T+A or Focal Stellia or Utopia cans this is great amp. Audeze cans has been a bit disappointing for me out of Envy, but this is probably due to a fact that overall I prefer T+A, Susvara or Focals over Audeze products at the moment.
Hope this helps