I think you’re mostly right, particularly when it comes to the settings dialogs in Windows which have been a state of ferment since Windows 8 such that I expect many of them to be reworked in several faddish ‘mobile’ phases while some will still look like they did in the Windows 95 era.
Comparing the various nag windows on MacOS and Windows, as much as they are annoying, the MacOS nags look like a 1999 rework of the modals from the 1984 original Mac whereas the web-based ones in Windows are easier on the eyes. I have looked long and hard at x-platform UI frameworks and they are generally pretty awful and with all the affordances the web platform has Electron looks good in comparison both in terms of UX and DX.
My beef is with the tabs-inside-of-windows, windows-inside-of-windows and the frequent need to have a large number of ‘items’ open and wanting some synoptic view of all the items open in all the applications on all of the virtual desktops a modern machine can have. I try pretty hard to keep it organized but if I am listening to music in YouTube it should be trivial to find the browser tab involved to close it and it’s not.
I’m reminded of the multiple document interface
https://en.wikipedia.org/wiki/Multiple-document_interface
Which was big in the Windows 95 era, particularly with Office that now seems largely forgotten. When Netscape 4 hit the streets Netscape changed their home page to use <layers> which were like absolute positioned <div>(s) to get an MDI effect like the page that started this discussion. Trouble was it didn’t work and they had to revert it quickly. I told my professor that I thought I wouldn’t understand how web pages worked in six months it was changing so fast but JavaScript supremacy took at least another 12 years even if Microsoft rolled out AJAX circa 1999 it took forever in internet time for people to get the significance.