I’d modify the script to do this when it imports the data. I’m surprised that it doesn’t already. It’s worth taking a closer look at things.
On several scripts that I’ve worked on, I’ve added an IMPORT_AFTER ENV setting and modified the queries to include where some_timestamp > import_after_data. I don’t think this one has such an option, but I haven’t paid careful attention.
But beware that it’s likely that things that are in the data from 10 years ago are likely to be different from the last 2 years, so testing on just recent data is great for debugging stuff that you know is everywhere, you’ll want to test on the whole database too.