Performance Insights for Aurora Postgres doesn't show any data

Because Performance Insights is a sampling method, queries that are completed in a short period of time may not be sampled.
In other words, I think the SQL you executed was not displayed because it was done quickly.

https://aws.amazon.com/rds/performance-insights/faqs/?nc1=h_ls

Performance Insights counts active sessions and records each session’s attributes about every second using a lightweight sampling mechanism. The sampled data is encrypted and aggregated to a variety of granularities and served through the API and in the DB Load chart in the Amazon RDS Management Console.