Forea

Thanks.
I dare not touch the templates.
Thats too much for me.

You need to be hosted by IPS directly. It is not available to self hosted installations as the real-time system requires modules not found in a traditional LAMP stack found on most hosting environments. 

That's another language string, which gives the name of the forum. You can't translate that; you'd have to edit the template to remove the call to forums_forum_x (or however it's called).

it will help if you change language to english and we can tell you where it is , post a larger image maybe too, from the place you see it. 
if you search it in the language  when you click translate :


it appears , in my  acp

They are both better than mine 😄 

Can't change your computer skills, but I recommend strongly the best online translation software:
https://www.deepl.com/translator
I use it myself often and it's great.

I see you have another Go To Top modification in that list. Based on the name it should do something similar, if not you can give this one a try instead:
 

Back To Top is most likely the culprit. I've seen plenty of forums going down because it's not compatible with PHP 8.
As for the logo, your old theme should still be there. You can just switch back to it. 👍

If you can get into the admin CP, you can of course disable applications and plugins from the support section of the admin Cp

You probably have an outdated 3rd-party resource (app, plugin or theme).
Tty the RECOVERY MODE.