Win+Right, Win+Left shortcuts not working in Windows 10

It's because the snap option has been disabled. Just open start menu, type Snap and select Snap settings. Alternatively open settings > system > multitasking

There you'll see the Snap - Arrange windows automatically by dragging them to the sides or corners of the screen. Just enable it and the shortcuts will work again

See also

• Win-Key + Arrow does not snap windows on Win10

If you close a window that is currently snapped then re-open it, it generally breaks one of the snap directions. e.g. if I snap VSCode to the right side of my screen, close it, then re-open it, Win+Right will work, but Win+Left will not.