Hi @Joost van der Linden,
I'm glad to hear you solve the problem ,if you have any issue about SharePoint, you are welcome to raise a ticket in this forum.
By the way, since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others." and according to the scenario introduced here: Answering your own questions on Microsoft Q&A, I would make a brief summary of this thread:
[SharePoint List item not found when running HTTP query from Logic app]
Issue Symptom:
Unable to get sharepoint list item by graph in Logic app. But could get data by postman
Solution:
When granting the Enterprise app permissions to the specific SharePoint site, we can only select read or write permissions, and this is insufficient to override the configuration (full control permissions required).
You could click the "Accept Answer" button for this summary to close this thread, and this can make it easier for other community member's to see the useful information when reading this thread. Thanks for your understanding!