this works: https://github.com/valinet/ExplorerPatcher

I mean if I'm at the point of having to monkeypatch the explorer executable, I might as well not use Windows...

Luckily with macOS there is the way of expose (renamed) and hot corners that allows switching based on various logic by a swing of the mouse both lightning fast and visual (easy and quick to locate things and trace what is happening), very natural to me from the very first time I tried. (this allowed Mac + VM products like Parallels with coherence mode to work superior to any Windows practice in this reagard - better in handling multiple windows than Windows, hehe - having Win in a VM was my preferred way of working with Windows for a decade or so - only changed because of new job with different IT practices, and lately with the looong transition of Intel to ARM processors and the consequent difficulties with x64 Win systems and apps. All Windows window became a Mac window, switching between those very visually and quickly, superior to Windows way, even with the then working taskbar practices)

Unluckily in Windows the taskbar became more essential than the dock in macOS for switching windows - on Mac I use the dock to start new instances or quitting the app (differing philosophy of window and app lifetime between mac and win), not much of a switching - and then they ruined this essential taskbar thing without good alternative on Windows (Ctrl + Tab is more like a complementary thing than alternative).

Probably different use cases but I've never found tools that show the window contents to be useful over the window title.

I almost always have many windows that would have thumbnails essentially indistinguishable from each other (think text editors, file managers, terminal prompts etc.)

So I use the task bar as almost like a system wide "tab" interface. Grouping stuff into the app icon is terrible because I can't easily tell if I have a window of the type I want already open. I don't click on the taskbar items to navigate, rather I use them to check what is already open so I can quickly keyboard switch to them.

The Win11 UI completely breaks this workflow so now I either need to do a linear search to flip through all windows, or pull up either the task view or hover menu above the app icon, and pray I can tell apart the huge grid of identical window thumbnails.

Exactly, ungrouped taskbar is the next essential thing after properly working Alt+Tab.