Komorebi works pretty well. In the end, I felt like it's limitations were mostly at the OS level rather than the fault of the software itself (similar to tiling WM on MacOs). I think for such a thing to really work, virtual desktops need to be a first class feature of the desktop environment. For Windows/Mac, they're still kind of janky. Whereas on Linux, I can bind Win+Tab to "Previous Desktop", hold down the button, and watch the screen flick between almost as fast as the refresh rate of the monitor. It really makes a laptop, with a small screen and with no additional monitors, a high productivity environment. Which is too bad, because the REST of Linux really sucks for laptops, with all the hardware-specific tweaks needed.

In Windows 10 and 11, after you create another virtual desktop, you can easily move between them with built-in Win+Ctrl+Left/Right Arrow. It may not be as perfectly tuned as many would like, but it works well enough.

You can disable the switch animation, which makes it much nicer to use. Just instantly changes the content on all your monitors then. It even works with fullscreen applications on different desktops...

Yep, under Accessibility => Display => Toggle the Reduce motion button. It is much better but still not instant. The only way I'm aware of how to make it instantaneous is by disabling SIP and using Yabai [1].

[1] https://github.com/koekeishiya/yabai