Hi @Daniel
There is no such setting could control all Teams channels to let users receive banner notifications whenever something is posted to the channel.
If the poster intends everyone to be notified, we recommend you use @mention the channel or the entire team.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.