Well, what your post suggested to me is that your ears work
Because the V90 is precise, it has great bass, real thump and power behind it. The treble is modest. But that's the thing, I think they went a little too far in making the treble "polite." Or it is just slanted towards the bass tuning.
Looking back, the initial reviews posted on Head-Fi seem to be accurate. They accurately characterize the strengths of the V90, which are many. But they talk about "dryness" and how the upper register is "thin."
I agree, and think that it's really an issue with that part of the register. The bass is plenty soul-ful.
Back then, lots of people were talking about it being a killer bass performer at the price, which is still true. But some people were also saying that they use it as a generalist IEM, that it could function as their one and only IEM.
I was like, "what?" I can see how it was one of the best choices at $32 and if that was all you had. But I could never use it for most acoustic music. So I thought that there was a tendency to overlook a less-than-natural upper tuning. This persisted.
Go look at the reviews for it on this site. I think they capture it accurately, including the thin upper register. I tend to watch and read a variety of reviewers and websites in order to get a more three-dimensional understanding of the IEMs. [Four-dimensional if we factor in time, and looking back.]
C10s and BL-03s are still great. I'm hoping the BL-05s will be the better-fitting BL-03.
I'm not sure what, if anything, has replaced the V90. Maybe the CA16 is that good, but I just need that one to be better than C10 or ZS-10 Pro. The ZAX or whatever is said to be highly capable, but I know very little about it.
EDIT: BTW I'm still fairly new to IEMs myself, but I had a similar experience with the V90 as you indicate.