Hi Fritz,

By right you should be able to remove it through edit website.

But, if you can't remove it. 

Here are few steps you can follow:

1. Open you "Source Inspection" or press F12 if you are in chrome. Follow the screenshot below for the steps
   
2. You will get the class name, that's the important part. In my case it's "o_wevent_sidebar_block"
3. Now, activate your developer mode. If you don't know how: https://www.odoo.com/documentation/18.0/applications/general/developer_mode.html
4. Go to Settings > Technical > User Interface > Views
5. Search for "o_wevent_sidebar_block" in the search bar and select "View Architecture"
   
6. You will see the record where this code is injected.
7. Next, open the Views record, look for the XML architecture below and comments the <div> with class "o_wevent_sidebar_block" along with the nested tags inside.
   
8. Save and reload your website. You should see that it's gone now.
   

Hope this helps. Upvote and solve if this answers your question.