I’m not 100% sure what the issue is, but I would check out the issue with the date mentioned above. You could also remove the taxa allowed (since it seems like you just want any observations, there’s no need to make it more complex by adding taxon requirements).
I think the main issue is probably that the location filter is a Google Maps location and that observations being made aren’t showing up in that location for whatever reason. I would suggest making a kml file for your place and making the boundaries a bit bigger than the actual site to accurate for coordinate uncertainty. You can see more info on this thread: https://forum.inaturalist.org/t/i-need-to-set-up-a-new-geographical-area-for-observations-in-a-specific-woodland-how-do-i-do-that-please/31428
As others have noted, you can change the criteria after the fact since a project like this is basically a saved searched, so you should be able to get all observations made as part of the bioblitz added with a little tinkering.