As you can see on the screenshot below, I can't delete my site. This command is missing under the menu item Website information. Also in the advanced settings I can't find any delete functionality.
Each team in Microsoft Teams has a team site in SharePoint Online, and each standard channel in a team gets a folder within the default team site document library. Files shared within a conversation are automatically added to the document library, and permissions and file security options set in SharePoint are automatically reflected within Teams.
You can refer to the following articles to learn more about the relationship between the Microsoft team and SharePoint Online:
As Susan mentioned, if you delete this site or this library, the shared files and history of all users in this channel will be deleted, and it is not recommended that you delete this site.
Despite not knowing any german, this is a screen shot of deleting a site and not a page. Secondly the 'Delete site' is beneath the sentence "alle websitee...". I cannot comment if it is there or not since the screenshot stops exactly before. Third the 'delete site' link is also available in Site Settings (which is your 'alle websitee...') under "site actions".
If you cannot get to Site Settings and see this command it means you are not site owner or the site owner permission level assigned to you as been modified.