Even with smooth deceleration, the earth bulges at the equator due to centrifugal force. If you decelerate smoothly, you pass through the zero-point (no rotation) which would mean the bulge would have to disappear. This wouldn’t happen smoothly, it would happen in bursts that we call earthquakes. And then the bulge reappears once the centrifugal force is restored in the opposite spin, again in bursts.

I mean, it’d take forever to do it smoothly, right? Like it’s spinning pretty damn fast if it’s able to rotate completely in 24 hours, there is no way it could go the other way for just 24 hours without that requiring everything you’ve ever known to be launched into the east like water shaken from a dog’s coat.