Welcome to the Airtable community!
It sounds like you are using the REST API. If you are using only the REST API, yes, you must do it 10 records at a time.
However, if you use scripting, it is possible to delete up to 50 records in a single call, and delete all records in a base in a single script. A script can delete thousands of records in a few seconds.
Here are some options:
Also, for those people reading this thread in the future who want a no-coding way of deleting all records at once, below is a screenshot of how you would set this up in Make.com.
Just tell Make to search for all of your records (by using the formula:
1), and then Make will delete all of your records.