even beyond getting this to work within the context of projects, i think you would need to get this to work in the context of regular filters when searching for observations. there’s a discussion here that describes some of the changes that should probably happen first before i think it would make sense to even attempt your feature request: https://forum.inaturalist.org/t/identify-filter-without-annotation-not-working-properly/30148.
your feature request is probably also a variant of https://forum.inaturalist.org/t/collection-project-using-without-annotation-filter/28212. that other one would probably have to happen first or in conjunction with your particular request here.