Good evening Felix and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the Google Map not displaying in single events.
I would love to help you with this topic.
The first thing I would recommend is to deactivate the Event Rocket plugin.
Although this has been a great plugin, it is no longer maintained and is known to break features since 4.0.
The good news is that many of it’s features are now a part of our other plugins.
Secondly, could you ensure you have a Google Maps API key set up as recommended here: https://theeventscalendar.com/knowledgebase/setting-up-your-google-maps-api-key/
Let me know if that helps.
Have a great day!
Geoff B.