I found the same limitation that was causing me issues as well. I don't know if this is the easiest way, but in the CSV before import, I added a quick column with today's date. Upon importing the CSV, it updated the date in Airtable for that column. I then had a View in Airtable filtered by dates prior to today. That quickly filtered out the old records that I then deleted. It added a few steps, but the time savings of importing a CSV was worth the trade. I hope this helps.