Oh yeah, the white whistles make perfect sense to a point. Sure, Bonedaddy would be a bit more effective if he gave his army guns but it isn't necessary nor does it make sense for the character. I can't really accept the idea of 'too burdensome' just based on having lugged a bunch of shit around before. A handgun and a hundred rounds is basically nothing when you have your long travel bag. It'd be hard to convince me that these professional delvers are worse at weight management than the good ol' US military. Heck, I wouldn't even expect the MC to have one because she's a kiddo.
You'd think the foreign delvers that go in to snipe relics off of proper delvers would have guns and thus proper delvers would need them simply because of that. I ain't saying that it ruins the story or anything, it's just something I constantly think about when they show the world other than Megaman, Potato and Bunbun doing their thing.