watch lists for planner tasks
In Teams (and Planner) add the capability to have a watch/notification list so that when comments are posted to the task, everyone on the watch/notification list receives an email with that update.
secondly, give an option for people to receive notifications immediately, as a weekly digest, or daily... just as you can do in Sharepoint.
In Teams, I have teams of people assigned to a task with a checklist so they are all aware of what has to be done and can check off progress. However, if there is an update, they AND ME (the manager) need to know the update as it impacts the team and the initiative. Additionally, there are other interested parties that need to be kept up to date but who should not be assigned to the task card.