This may help, but I’m aware not direct experience.
I use a Nordost Blue Heaven cable on my ZMF Verite. I bought it deliberately to ‘open up’ a warmish headphone and slightly constrained treble-and it does just that. It also carries lots of detail and sounds very ‘clean’. Suits some music and moods for me to swap it for the stock cable.
The Utopia (and Stellia, which I have tried on the stock cable) are not known for lacking detail or being too warm/lush. In fact I didn’t like Stellia for being too detailed and a bit bright and ‘technical’ sounding. So I would strongly suggest trying the Nordost before buying, as I think there is a risk it might bring out those existing characteristics a bit too much. Cable/can synergy is hard to predict but maybe a dealer can lend you a short one before you commit more money to 5m?
It is nicely made but the main section is rather stiff and inflexible if that bothers you.
I will be getting the Cardas Clear HPC cable. 4.5 meter for my Utopia. Lemo at the headphone end 1/4 inch at the other end. Using with SN3, CD5si, NDx2, P9 TT
I own the original Utopia headphone. I purchased it many years ago.
I upgraded the stock cable to a Lazuli Reference cable made by Danacable in Colorado, USA. The Lazuli Reference cable opens up the top end, it provides more detail with better instrument separation and it presents the bass with more authority.
In my opinion, the Lazuli Reference cable transforms the Utopia headphone: the headphone went from being very good to great.
@razzzor1963 i looked at that cable and it would be well over $2500 for the length I need. Ouch. I looked on thier website and they don’t even list 4.5 meter cables. I emailed them, but it could be well beyond what I want to spend. I got an email back from the company. Their cable recommendation for the 2022 Utopia was less than $2500, but not much less. Much more than I want to spend.