How can I keep a display’s rotation after sleep or restart?

Set the display to the angle you want, then enable Configuration Protection > Rotation in that display's App Menu block. BetterDisplay saves that angle and attempts to restore it if it changes.

Configuration Protection requires Pro. BetterDisplay must be running, and the connected display must still support rotation. It cannot apply the setting before the app starts or force rotation on an unsupported connection.

Check the protected angle if you later rotate the display through BetterDisplay: changing the rotation can update the saved protection. If a dock or KVM makes the display appear as a different device, compare its identity before and after reconnecting as well.

See Configuration Protection for saved properties and enforcement behavior. If the property that disappears is a refresh rate rather than rotation, see protected refresh-rate limits.