I submitted a FOIA request to the CBP for entry and exit records on 2020-10-21 and got a response with those records on 2020-12-10. I have no idea if that time is typical or not.
The fee charged for this was $25. The data was delivered online at https://www.foiaonline.gov. It looked a lot like an Excel spreadsheet printout.
I found some contradictory feedback:
If you are unable to locate your travel history records through the methods listed above, you can submit a Freedom of Information Act (FOIA) request to U.S. Customs and Border Protection (CBP). Generally, personal FOIA requests are free (if less than 100 ...