Just to note that there’s a discussion of Daniel Boyarin’s recent claim that [premodern] Judaism is not rightly characterised as a ‘religion’ (in the modern sense) at Marginalia, and a reminder (which I had forgotten) that Brent Nongbri published a book a while ago arguing (similarly to Preus, Z Smith, McCutcheon, King, and others) that ‘religion’ is strictly a modern Western notion which may be useful in the analysis of premodern (and presumably non-Western) phenomena, but only with painstaking self-critical caution. Reviews abound.
The literature on this sort of controversy far exceeds anything I can adequately bibliographise here. You’re welcome to add favourites in the comments, but I’m not myself going to try to keep logging every useful publication on ‘religion’; I have other fish to fry (or more pertinently in my case, ‘other tofu to stir-fry’).