I don't think HexOS point is to be solution for all, actually, a custom solutions will always be better for edge cases or non-general thing.
Of course they could in future, and in far future make toggle for different features in installer, but to my understanding HexOS point is to be "plug & play" solution for most.
My NAS / home server runs on NixOS, which is heavily optimized to memory and CPU right now, and I don't think HexOS can even get ever as slimmed down as that, but I'm still switching for HexOS when I get key, to simpler management, and for that Plug & Play feeling.
If your requirement is to have minimal RAM / CPU I would recommend to look other solutions, most likely custom one would fit you best.