Have you heard both pairings, HMS/TT and HMS/TT 2, for a long time in a known system? I have heard both pairings for several months each in my own system. If not, by all means state your opinion... but maybe (MusicKid) in a slightly less dogmatic way? Enjoyment of music is subjective, not purely logical... so comparing figures may not show the whole picture.
OP specifically stated one purchase only is feasible and that the TT drives their current headphones just fine : no one knows for certain what will happen in their future re finances and purchases - let alone now.
Upgrading to HMS with TT in my system gave me much more of an increase in actual listening pleasure than swapping TT for TT 2 (using both with the HMS).
HMS/TT 2 may be the ideal (excluding HMS/DAVE?) but for a single expensive purchase, in my personal experience, TT 2 (vs. TT) is much less important than adding HMS in enjoying music. Putting the HMS into bypass (for me) gives a major loss of enjoyment with either TT DAC.
Cheers,
Hugh