what depth of information are you talking about? the synth outputs sound. It might have a small screen. there may be knobs with number scales. but overall you aren't taking a ton of information out of a synth.
You may be pulling in signals from bananas (literally), driving them through a dozen modules with three times as many patch cables and using them to drive a video signal and a few stepper motors alongside your audio out.
And you’re doing it with a lot of bespoke little modules made in small batches, sometimes with faults, and almost always capable of things that were neither envisioned or documented by their original designer.
It’s a whole different world than guitar pedals or even a single big commercial synth (which is what your description sounds like).
It's not a modular synth, but quite the opposite... it's a digital synth which is more like a computer than, say, a minimoog.
It has a great UI and much of what it does it shows you very well.
Still, it has a massive modulation matrix, in which the 5 LFOs and the 5 Envelopes can be sent about anywhere, often controlling the 3 oscillators or the 2 filters.
And in order to actually see the 10 or so setting for each of those 10 modulators going to the myriad of places that they could go (and noting that you can route the oscilators themselves to various points) you have to have both some willingness to dive around the small menus or some knowledge of how the patch was created.
That's nicely facilitated by the UI which has a lot of nice buttons for quickly selecting element, but still.
By contrast, you can look at your modular synth and see the physical connections which reveal the routing of the patch. While there are all kinds of things that can hide the complexity such as normalized connections within devices or devices that have their own micro-controllers doing who knows what, the network of wires is, itself, quite a lot of information.
a modular synth is like a totally custom rig that nobody but you can understand, because you built it. It's bad ui from step 1.
For playing a gig, the Hydrasynth is a far better UI.
But in general, all these rigs are very specific to their users. I've brought the HS to a lot of traditional jams where keyboard players are.
Most folks can't come up and perform on my hydrasynth, either, unless I show them which 3 knobs to play with for a specific patch.
Each patch is "like a totally custom rig that nobody but you can understand, because you built it".
Anyhow, the question is how much information is displayed at a glance, not "quality of the UI", and your original comment ignores a lot of that information. I'm sorry if pointing that out didn't feel nice to you so you decided to move the goalpost.
I don't think modular synths do a good job conveying lots of information since I have to trace wires across multiple components to try to figure out what is modulated by what. That information is not available 'at a glance'.
They're highly configurable and thus flexible in what they're capable of, but I don't think they convey information well at all.