To take a step toward the clean, minimalist look you see in the Microsoft 2019 video, hide window borders when not hovering the cursor over them (or near them, user adjustable option). Either by making them transparent, or if that's not possible, overlay with some user-selectable solid color (usually the desktop background color), like in this mockup:

When hovering over or near the border, the color would be removed but could also be changed to transparent and tinted so that the borders "glow" or simply changed to some other solid color (width and position adjustable - if not using the border width system variable - so you could cover only parts of the border, for example leaving the outermost or innermost line visible). If you can actually remove them so that the windows would tile seamlessly, that would be an option, but just hiding them would be fine.
It certainly can be done as seen in this tiling window manager:

http://hashtwm.demonastery.org/
This http://www.autohotkey.com/docs/commands/WinSet.htm would seem to do the job (though I'm not sure) and has even rounded corners which would be a bonus (user option, adjustable roundness).
http://www.donationcoder.com/forum/index.php?topic=19584.msg179289#msg179289 lets you blank out the window titlebar (and taskbar) icons and buttons when not hovering over the titlebar. It seems you'd only have to change a bit of code there to get this app done.
That app is needed for getting that ultra-minimalistic look. Perhaps it and this one could be combined.
The app could, optionally, also hide the window titlebar, and also the statusbar, and scrollbars, when not hovering near them. It would optionally actually remove the titlebar like in the tiling window manager, but when the cursor is near the titlebar area, it pops up.
A separate bonus snack:
To get rid of the last piece of visual clutter, I'd also like to have the My Computer/Internet icon removed from the Explorer statusbar. Simply filling that area with a solid color would be an acceptable solution. The user would have to match the color and perhaps the height to the visual style - unless there are system variables for those.
Also see http://homepage1.nifty.com/kazubon/tclocklight/ for getting rid of the visual junk in the taskbar.

When hovering over or near the border, the color would be removed but could also be changed to transparent and tinted so that the borders "glow" or simply changed to some other solid color (width and position adjustable - if not using the border width system variable - so you could cover only parts of the border, for example leaving the outermost or innermost line visible). If you can actually remove them so that the windows would tile seamlessly, that would be an option, but just hiding them would be fine.
It certainly can be done as seen in this tiling window manager:

http://hashtwm.demonastery.org/
This http://www.autohotkey.com/docs/commands/WinSet.htm would seem to do the job (though I'm not sure) and has even rounded corners which would be a bonus (user option, adjustable roundness).
http://www.donationcoder.com/forum/index.php?topic=19584.msg179289#msg179289 lets you blank out the window titlebar (and taskbar) icons and buttons when not hovering over the titlebar. It seems you'd only have to change a bit of code there to get this app done.
That app is needed for getting that ultra-minimalistic look. Perhaps it and this one could be combined.
The app could, optionally, also hide the window titlebar, and also the statusbar, and scrollbars, when not hovering near them. It would optionally actually remove the titlebar like in the tiling window manager, but when the cursor is near the titlebar area, it pops up.
A separate bonus snack:
To get rid of the last piece of visual clutter, I'd also like to have the My Computer/Internet icon removed from the Explorer statusbar. Simply filling that area with a solid color would be an acceptable solution. The user would have to match the color and perhaps the height to the visual style - unless there are system variables for those.
Also see http://homepage1.nifty.com/kazubon/tclocklight/ for getting rid of the visual junk in the taskbar.









