I saw a feature in my OnePlus 7 Pro where in when the display is in landscape and a message is received, the reply would bring up the keyboard in a similar size as if it's in portrait on one side while the message thread is on the other side. Mot sure if this is OP specific or Android version specific. So far, the apps that shows it support it is whatsapp and instagram in my list of apps. The setting is called Quick Reply in Landscape.