Minimize Sidebar in Messages on iPad

The Messages App window has two elements - the message list (to the left) and the conversion window (to the right). When referring to the “sidebar”, I presume you refer to the message list.

There are no settings to control the appearance of elements within the Messages App window. The message list cannot be suppressed from view.

Apple invite submission of feature requests via its Product Feedback portal:

Product Feedback - Apple

The Messages App window has two elements - the message list (to the left) and the conversation window (to the right). When referring to the “sidebar”, I presume you refer to the message list.

There are no settings to control the appearance of elements within the Messages App window. The message list cannot be suppressed from view.