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.". So, I would make a brief summary of this thread:
[SharePoint list view looks strange]
Issue Symptom:
Event list looks strange. And JSON codes don't work in the new list experience.
Current status:
OP solved this.
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!