@mdeguerre welcome to the community and apologies for the delay in getting back to you. I’ve opened a ticket with our tech support team to look into this. They’ll likely ask for a link to the BigQuery project. If you don’t mind DM’ing that to me, I’ll add it to the ticket. 

Hi @mdeguerre ! Welcome to Amplitude Community If you want to do a backfill of your historical Amplitude events to BigQuery, you should be able to manually start a sync of your historical data: https://www.docs.developers.amplitude.com/data/destinations/bigquery/#:~:text=manually%20start%20a%20sync%20of%20your%20historical%20data 

After you create the destination, you should then be able to see a Backfill tab that will allow you to configure the date range in which you would like to backfill the data. Hope this helps!