Which parts are you having difficulty with?
I want to change the proportion between 1 and 2:
https://www.marginalia.nu/junk/resize.png
Not only do I need to guess which of the 3 horizontal bars is the resizable one, it's literally a single pixel in height and very hard to click.
Flat design is such a regression in terms of UX it's difficult to comprehend how intuitive the Windows 95 style was, largely from reliance on universally familiar spatial metaphors.
That's ignoring the fact that none of the icons have labels so you have to learn the Mayan alphabet to figure out what they do (and these icons change sometimes too!)
It also seems like preference dialogs have just sorted given up any pretense of trying to make sense. Instead of navigating a hierarchy, I'm supposed to guess which keywords to search for in order to find the correct option I want to change. It's a real downgrade. The affordances of search boxes are notoriously ambiguous for this exact type of task. I want to change the pixel scaling on the screen. What do I search for? Screen? Display? Resolution?
Remember when the file menu was removed and you couldn't figure out how to save your work? Oh, it's that decorative symbol looking thing in the corner above everything else. And when you click it, there isn't a menu at all, but a huge control panel thing appears.
Every user that creates something wants to save it. This is not where you put the save command.
Amen. Obsidian is a good example of what you are talking about. So many different icons I have to remember plus the way to search my notes involves clicking on what appears to be a text label (Files) to reveal the search icon.
One thing I've thought about is some kind of "Quick tooltip", like a toggle to make the UI always show tooltips instantly on hover. That could be an accessibility feature built into the OS.
A light theme would be much more likely (though certainly not guaranteed, since the flat craze began) to have a light grey background on the panel title, a white background on the panel contents, and no border between the two (or at least a lighter grey than the inter-panel border), so that the only border (or at least the strongest border) would be above the panel (that is, above the panel title), making things much clearer. (The panel toolbar would also tend to get a light grey background, similar to the panel title’s or between that of the panel title and panel contents.)