We have a GA4 export link to BigQuery since 10th of December.
However, we have only data for the last 60 days.
What's checked so far:
1. GA4 retention is set to 14 months, from the start of the exporting process.
2. We have a billing account linked to our BigQuery project.
3. Dataset expiration is set to NEVER.
In this account we have four more GA4 to BigQuery exports, which are setup identically, and they all work properly.
Most probably the only think we are missing is the contact method to Google support team..>
BR
Blago