I managed to make an entry type that won't let me create any entries. How can I fix it?
It sounds like you're trying to have a dynamic title for that section, based on an Entries field (Venue). Working out the nuances in this situation can be a little tricky, but I think this would do the trick for you:

{{ object.venue.first().title ?? '(no venue)' }}


Let's break down what's happening here...

In this use-case, object is your Entry. Which means that object.venue is your Venue field (which happens to be an Entries field type).

Since Venue is an Entries field type, that means it's going to return an Element Criteria Model. When dealing with an ECM, you need to append something like find() (get all) or first() (get one) to end up with an actual, useful result.

Once we've established that you only need a single Entry (object.venue.first()), let's go ahead and grab the title of that Entry (object.venue.first().title). The good news... that can all be chained together! The bad news... it'll throw an error if the Venue field is left empty.

Which is where ?? '(no venue)' comes in. The double question mark is called a null-coalescing operator. It provides a graceful fallback, suppressing error messages and allowing you to provide a safe alternative.

Put it all together, and you'll have a nice, safe dynamic title.