I've just had a similar experience to OP
My "current" DAC is the Cen Grand DSDAC 1.0 Super Clock, which is a fine DAC, absolutely nothing wrong with it but .....
I've had an itch to re-try R2R DACs again. I had the Ares II about 2yrs ago or so but sold it, probably a little hastily and funded my REL sub with the proceeds. My system back then has no resemblance to what it is now, and I just wasn't hearing what all the fuss was about with the Ares II in my system at the time.
About 5 weeks ago I spotted a pre-loved Ares 12th-1 up for sale on the auction site, so I bid and won.
I fell in love with this little DAC; while the Cen Grand is very good, the little Ares 12th-1 is just so engaging and enjoyable. I can't bring myself to plug the Cen Grand back in. I'm not sure now, what to do. Just like the OP, I can't unhear what I've heard, and I have a DAC that cost x3 what the little Ares cost, just sat there redundant. I'm going to sit on it for little while longer, and make a decision