I would expect the Merason to immediately sound more harmonically correct with better performance at the low and high ends. However all upgrades carry the risk of unintended consequences, be prepared that masked weaknesses in the streamer may be exposed with a better DAC. The main difference between a $1k and $4k streamer IME should be more sophistication in detail and better resolution of background instruments. My first separate DAC years ago was a Dlink III and it was enlightening on how DACs were important.
Do you recall "instant improvement" from your first stand-alone DAC ?
After weeks of research I recently ordered my first external DAC. My system is modest by most accounts... Van Alstine SET400 amp, T-10 tube pre-amp, Salk HT2-TL speakers, WiiM Ultra streamer/DAC. It sounds very good to me... resolving, clear, excellent bass, mids, highs. Then I started reading and asking about streamers and DACs and it seems my system could sound better. So I did a lot of reading and ultimately ordered a used Merason Frerot with factory wal wort power supply. Now the anxiety of second-guessing my choice and what it will sound like in my system. Cuz there are no stores near me to demo DACS. Eventually I will likely upgrade the streamer.
What did you notice the most about your first stand-alone DAC... more clarity, richness, scary good vocals, extended highs, more airy highs, more and better bass ? Better soundstage and imaging ? All the above ?