Hi @Marco1384 I hope you are well!
Yes you're right it is hard to pinpoint chats for guests who are checking-in soonest in the messaging inbox, and I don't think there is a way to sort them currently. (they just appear in most recent order)
What I do is use the Calendar section on the app, scroll down and this lists all check-in/outs/on-going stays by date, (most recent first) and you can message the guest from here- also from the calendar of your listing itself.
Being able to sort the inbox is a wonderful idea though!
Paul 🙂