Reporting back after a ton of research and experimenting.
I've been demoing the LTA Aero and Mojo Mystique Y in my system this last week and thought I'd share my early impressions. While waiting about a month for these to arrive, I also tried some other speaker cables. Supra 3.4, Mogami w3104, Oyaide Tunami v2, and Neotech 3001. I had some excessive brightness/harsh treble that made some tracks hard to listen to. Speaker cables made a huge difference surprisingly and each of those upgrades provided noticeable improvements!
System now is Roon Nuc - Ifi Zen Stream w/ elite LPS - DAC - Luxman l509x - Spendor D9.2.
I previously had a Lumin T2. I don't think it synergized well with the spendor Ds and luxman. It was too detailed and analytical for me for speakers which already lean a touch that direction for my tastes.
Both of these DACs completely changed the system for me. Albums I previously thought were poor recordings revealed by my revealing system are now enjoyable. There is more weight, organic richness, tone and life to the music. I could happily live with either one. Its going to be difficult to decide.
I swapped tubes in the Aero to the Ray Tubes Reserve 6sn7. That changed the character of the Aero and made me realize how tube rolling can influence the sound. The 6sn7 toned down some of the incisive zippy nature of the Aero and gave more tonal richness, lifelike insight into the music. I've also been trying a Cary SLP-05 tube preamp into the separates input on the luxman which is pure magic. The Aero with stock tubes straight into the Luxman gave perhaps 30% of the tube magic vs including the Cary in the chain. The Ray Tubes Reserve 6sn7 gets me 70% of the tube magic while retaining more of the drive and solidity of the Luxman preamp. The aero with the 6sn7s into the luxman I would describe as spacious, detailed, insightful, organic, rich, airy and alive. The band sounds in my room vs listening to a great recording. Acoustic and jazz shines.
The Mojo also sounds fantastic and swapping back and forth between the Aero and also including the Cary preamp it's difficult to nail down a clear winner. The Mojo is smooth, dense, very composed and clear. The soundstage is a touch narrower but more dense. It is even handed. It also has similar giddieup to the Aero with the 6sn7 tubes (although not as much as the stock tubes which want to boogie). I seemed to like the Mojo best relative in comparison to the Aero with more produced music like Abbey Road or an Eryka Badu album.
At this point I'm leaning towards the Aero with the upgraded tubes and sticking with the Luxman vs going tube pre / ss power amp. It gives me some of the tube magic while keeping the setup simpler and it sounds fantastic. Its a tough call though, the Mojo also is a lovely DAC. The Cary is special. I have more listening to do. Thanks to all the folks on this forum sharing their experience. Really happy with how things are sounding over here.