I purchased a TT2 about six months ago, and my next upgrade was the LTA MZ3, which I primarily use with my Focal Utopia headphone. For me, the TT2 already provided a significant boost in resolution, so I didn't rush into getting an M-Scaler. I might consider it in sometimes this year of next year. In the meantime, I am enjoying the synergy between the TT2 and MZ3. The TT2 delivers very good resolution for me at the moment, while the MZ3 adds a bit of that "tube magic" without the usual heat and lengthy warm-up times—just 15 seconds to get up and running, which is incredibly convenient for a tube amp.
Regarding streamers, I'm currently using Audirvana on a Mac, connected to the TT2 via a Tubulus Concentus USB cable. I had planned to upgrade my streamer next, but I'm holding out for more options with Audirvana Ready support. I prefer to stick with Audirvana because I appreciate its EQ capabilities via plugins. For instance, I usually add a low-frequency shelf filter of 3dB when using the Utopia directly with the TT2, and with the MZ3, I often boost the lows further with an extra 1dB or more.
So, if you're considering your next move, think about what will enhance your listening experience based on your current setup and preferences. For me, the MZ3 has been a great addition. I’m not in a rush to rapidly upgrade my system anymore. I’m content with what I have and happy to enjoy it until I feel the need or the want for further improvements.