Google Messages is now receiving an update like quality-of-life which is fast marked as read/unread by swiping in the main conversation list. This feature is available on Google Messages version 20230515_01_RC00 users are using this.
In this update the feature of read or unread on Google Messages is not new for users but before they need to long-pressing a conversation and open an overflow menu.
Earlier, to archive or delete messages users use swipe action. In the Android notification sheet there you can easy and combine Mark as read.
At last, currently, this feature is available on Messages beta on many Pixel devices.
