As a member of a Microsoft 365 Group, you can choose to be subscribed to the group or not.  You are still a member of the group either way and can still access all of its conversations, files, notes, and events via Outlook Web App or Outlook even if you unsubscribe. However, you will not receive email messages for group conversations, and you will not be automatically invited to items put on the group calendar.

Subscribing to a group

When you subscribe to a group, you are requesting that conversations or events from the group be sent to your inbox. If you prefer to use Outlook instead of Outlook Web App, it’s a great idea to subscribe, because it ensures that you will receive group email messages and calendar events in Outlook in a timely way so you can stay up-to-date on group activity. You can also reply to the conversations from Outlook, and the replies are immediately posted to the group conversation. Subscribing to a group is also helpful when you are actively working in different groups and related projects, and want to stay on the top of each conversation and calendar event from your inbox.

Subscribing is enabled by default.  Each individual can enable or disable subscribing to a Group to suit their individual preferences.

If you think you are getting too much information from the group in your inbox, you can always unsubscribe from the group to reduce the information flow. The conversations are still available in the group, so you can revisit them from time-to-time to catch up on past conversations. There is a convenient unsubscribe link at the bottom of all group email messages.