Requirement: To deactivate a group, you must be the admin of this group.

If you deactivate a group, it will be removed from your group overview. In this case, however, the group is not permanently deleted and can therefore be activated again.

Note: A deactivated group disappears from the group and chat overview for all members. If you just want to hide a group from your chat overview, you can archive the chat. This is then hidden only for you and appears again as soon as a message is sent to the chat.

For more detailed information, see the article: What is the difference between deactivated and archived groups? ‍

You can reactivate a group by accessing your group overview.
Here you will find the “Disabled Groups” option.

Then select the group you want to reactivate.
In this group, click "Settings" and then "Activate Group."
This will then be displayed to all members again and is available both in the chat and in the cloud.