> After nearly 30 years of tech life myself, I've come to the realization that the best UIs are not graphical. They can have graphical elements mostly for visualization purposes, but all of them should be as minimal and unobtrusive as possible. Any interactivity should be primarily keyboard-driven, and mouse input should be optional.

I agree, that the interactivity should be primarily keyboard-driven. However, mouse input is useful for many things as well; if there are many things on the screen, the mouse can be a useful way to select one, even if the keyboard can also be used (if you already know what it is, you can type it in without having to know where on the screen it is; if you do not know what it is, you can see it on the screen and select it by mouse).

> Forcing users to click on graphical elements presents many challenges: what constitutes an "element"; what are its boundaries; when is it active, inactive, disabled, etc.; if it has icons, what do they mean; are interactive elements visually distinguishable from non-interactive elements; and so on.

At least older versions of Windows had a more consistent way of indicating some of these things, although sometimes they did not work very well, often they worked OK. (The conventions for doing so might have been improved, although at least they had some that, at least partially, worked.)

> A good example of bad UI that drives me mad today on Windows 11 is something as simple as resizing windows. ... it's not clear where the "grab" area for resizing a window exists anymore

I had just used ALT+SPACE to do stuff such as resize, move, etc. I have not used Windows 11 so I don't know if it works on Windows 11, but I would hope that it does if Microsoft wants to avoid confusing people. (On other older versions of Windows, even if they moved everything I was able to use it because most of the keyboard commands still work the same as older versions of Windows, so that is helpful (for example, you can still push ALT+TAB to switch between full-screen programs, ALT+F4 to close a full-screen program, etc; I don't know whether or not there is any other way to do such things like that). However, many of the changes will cause confusion despite this, or will cause other problems, that they removed stuff that is useful in favor of less useful or more worthless stuff.)