sentry issue across projects: n+1 query problem

[gregorpirgie]

Describe the bug
Response times for certain requests are unreasonably long. Sentry catches this and describes the underlying issue as n+1 query problems on the ORM / SQL layer.

To Reproduce
It's not an error and doesn't produce an error output. But see this example issue (many similar issues can be found across apis-vanilla instances in sentry)
https://acdh-ch.sentry.io/issues/3828213359/?project=4504360844394496&query=is%3Aunresolved&referrer=issue-stream

Expected behavior
The queries should be optimised to improve performance.
See fixes below.

fixes
Sentry provides these two links on how to fix this common problem:

• sentry n+1 problem
• article on n+1 problem

Additional context
It's a problem in apis-vanilla and potentially in apis-rdf as well.