Quick answer: Valve's October 26 Steam client beta fixes a crash when resuming from suspend, adds a workaround for updates hanging at 99%, gives friend game invites their own widget in the chat tab and starts local Remote Play streams faster.
Valve shipped another Steam client update to the Beta channel on October 26, and the notes are posted on the Steam Deck news page. The first fix on the list is a crash when resuming from suspend. Valve also added a workaround for updates that occasionally hang at 99%.
Most of the rest is about chat. Game invites from friends now get their own widget in the chat tab, right above the text box, so you no longer have to scroll back to the exact message in your chat history. In group chats, invites from individual friends now show up in the group chat window too, instead of only in that friend's 1-on-1 chat tab.
Valve also improved the group chat layout and fixed spots where gamepad navigation could get stuck. Friend chat notifications are now rolled up, instead of one 2-second notification popping up for every message. The chat tab's styling was updated to show which item is in focus more clearly, and in Big Picture mode the per-friend voice chat volume levels are now in the friend context menu.
For Remote Play, Valve says streaming now starts faster when you connect to a local computer.
All of these changes are in the Steam client's Beta channel for now.