You used to be able to move the taskbar to any side of the screen. IMO the more sensible move for widescreen monitors is to move it to the side so it takes up less screen real estate. Windows 11 removed the ability to move the taskbar like that; it's stuck on the bottom (unless you seek out 3rd party software solutions).
Also it should be noted that (at least as recently as September, haven't used 11 since) you could move the start button back to the left side.