How Do I Select Multiple Keynote Slides for Deletion On iPad?

I have very large Keynote file (1.42 GB, 2200+ slides). It’s so big, my Mac can no longer open it. Fortunately, I can still open it on my iPad Pro. I’ve duplicated it on my iPad with the intent of making Parts 1&2 by deleting opposite halves of the presentation in each duplicate file. But it seems I can only select multiple slides one at a time, which is going to be quite time consuming to select about a thousand slides for deletion, and then doing it again in the second file.
In Keynote for Mac, I can use the shift key to select the first and last slides in a series to quickly delete large groups of them at once. Is there a way to do this on iPad? Will I need to get a bluetooth keyboard perhaps?
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Cameron