I own a12t (custom variant of u12t), original Zeros and red Zeros. My humble opinion: blue Zeros sound great (albeit a bit shouty in upper mids for my ears, blame my tinnitus), red Zeros are perfect for me and a12t are embarrassingly bad in comparison. Upper midrange and treble are nowhere to be found and there is way too much bass (even with the m15 apex module). They sound muffled, heavy and wrong. All the detail is squashed, vocals sound unnatural, guitars don't have bite…The only redeeming qualities of a12t are 1) the looks and 2) the comfort and noise cancellation, since they're molded to my ear canals. But still, I never use them because I can't stand them without EQ and it's a big pain in the butt to fiddle with the Qudelix 5K on the go in comparison to the tiny USB-C dongle I use with red Zeros.
My advice: let go of this "dragon". I'm telling you from my very expensive mistake of an experience — u12t only seemed amazing to you because of the atmosphere generated by the price tag, the context and the looks. I remember when I tried them the first time in a super fancy IEM store in a fancy area of Scottsdale, AZ, they sounded amazing. But when I flip between my a12t's and red Zeros at home, that magic is replaced by a sobering and painful realization that my brain was tricked by the atmosphere of that fancy place.
If you have 2K burning a hole in your pocket, spend it on records or travel. We have more than enough proof that expensive in-ear jewelry is not worth it.