Prepare posts, but then hide them until you want people to see them
It would be good to prepare a post on teams fully but choose for it to remain hidden until you click to make it visible to all. This would all you to prepare without worrying that students may already do it and then turn up expecting more straight away.
Related - you could add a timer function here too. If I was 'away' and wanted to set my posts to appear tomorrow so I didn't have to login to do it manually I could set a time that they would be published automatically.
Same goes for settings for other aspects of Teams: surveys, meeting backgrounds etc. An ability to chat to , meet with yourself would provide all this. I'll raise separately as more general approach.