They were harsher than most contemporaries on queer sex, or really any sex outside of the purpose of procreation. Pagan religions at the time had little such compunctions. At most they were against excess. Or looked down on certain practices without banning them.

As for what God is, Christianity kept one part and added two more faces (but oh no they are definitely not three separate gods).

Honestly, I can't think of a (not recently invented) religion that is more similar to Christianity than Judaism (from which it came) and Islam (which was heavily inspired by it), especially not Christianity's main rival to overcome, Greco-Roman paganism. Other older religions are even more different.

Anyway, you sound like you have a horse in this race. Like you are either Jewish or Christian and feel almost offended about your "real" belief being compared to the other "wrong" one.

Most of the anti-sex mentality comes from Judaism. The monotheism and denying the existence of other gods as well. The idea of a perfect creator god. And everything else from the Old Testament that Christianity still considers valid as opposed to just being historic.

And yet it did shape it a lot.

Perfect things don't break down. Breakage happens through imperfection. Except, I guess, if them breaking down is a feature and they break down perfectly. At which point we are back at the "on purpose".