Thanks for this, for a portable set up I can only share I have tried both Utopia versions with. Cayin N8ii and the Chord Mojo/Poly combo. Of the two I greatly preferred the N8ii, despite both portables having plenty of power to drive the Utopia there was something holding it back.
I noticed you described the original Utopia as brighter in a previous post, assuming you are describing tonality then that is a half assessment compared to the U22. On the latter there is an obvious shift in tonality towards the lower end, whereas the original has a more balanced sound profile which some may consider bright or shouty if they tend to enjoy a smoother presentation.
I look at their major differences as the original being very resolving to a fault, and the U22 being more amenable to a variety of genres and quality of recording. While this area may be of importance to me, it may not to the preferences of others.
An aspect I find they have in common, despite the tonal shift, is with amp pairing. For my preference is tubes for both models, something you discovered with the Macintosh experience. When it comes to solid state amps I have owned and demo’d a decent variety while using both Utopia versions, majority of them are well regarded in this forum and unfortunately all desktop systems.
Now here is my controversial take with a fan favorite tube amp recommendation mentioned several times; MZ3 and either Utopia was not my cup of tea, did not bring the tube goodness I enjoy. It came across as a solid state amp along the lines of the Pass HPA-1 rather than my tube amps or the solid state amp pairings listed below.
Which solid state amps passed muster for me; DSHA-3F, Ferrum Oor w/Hypsos, and Bryston BHA-1 (this amp is the everyman amp in terms of does great with a lot of different headphones, yet doesn’t stand out in any particular area). Some which I did not care for; Pass HPA-1, Headamp GSX mini (ouch my ears), and Chord TT2 (wall of sound with too much in your face)
You will notice I did not mention any cables above, I found that an upgraded cable will not save a component. It will either make it better or do no harm, obviously a generalization from my experience which has shown this to be a trend. I will freely admit I am not one to hear significant changes with cables outside the basement bin offerings. I can say the stock Utopia cables are not bad sounding and are made of quality metals, 100% their aesthetics are less desirable compared to aftermarket cables. Whether this plays a role is not for me to say.
Long winded, hopefully gives you some better insight. However I will end with this suggestion which is from @Mon Shit List:
Portable: Getting a lot out of it on the go, focused a bit more toward the higher end
DAP: Luxury & Precision P6 Pro >OR= Lotoo PAW Gold Touch Ti >OR= Questyle QPM
Amp: Mass Kobo 424/428 >OR= Woo WA8
https://www.sonusapparatus.com/2023/05/m0ns-shit-list/#shortlist
Now for some brutally honest advice, if your passion lies in speakers. Use your current chain as is and focus your funds toward a speaker upgrade, or another component such as a DAC or Amp.