If you want to adjust or fine tune the notifications you're getting from a channel, here's how:
Go to the channel name and select More options > Channel notifications. This allows you to get notified of channel activity.
From there you can choose where and what notifications you want to get.
Banner and feed will send notifications to your device and to Activity at the top left of the Teams app. Feed will skip sending notifications to your desktop and will only show up in your activity feed.
Want fewer notifications from a channel? You can turn them off from here as well.
Below are the different types of settings you'll find in channel notifications:
All new posts will notify you each time someone starts a new conversation in the channel
Include all replies will notify you any time someone replies to a conversation
Channel mentions will notify you whenever someone @mentions the channel
FYI, Reset to default will turn on notifications for each item and will notify you in your activity feed and send desktop banner notifications.
To further customize your notification settings, see Manage notifications in Teams.