How to speed up duplicate detection in Photos

I recently got around to "merging" thousands of duplicates. I thought that all of my duplicates were gone. I did some searches trying to find photos I no longer needed, and I saw more duplicates, many more. I left Photos open overnight and this morning it had found 3 more duplicate pairs, 3!!

Is there a way to speed up the duplicate detection process, some settings somewhere?

Maybe start a manual scan?

Does it require iCloud in some way (I disabled all iCloud except find my mac)?

I have an M1 mac, so it is no slouch. Has anyone else been able to get better, or faster results with the duplicate scan?