Hey Merlin, as I am a total „Passes-Minimalist“, mabe my workflow is not representative.
Just at first sight, I was surprised that you render out so many separate passes.
So, yes, to me those are lots of them.
I guess I will also once experiment around with what benefit I can gain in post with some of these passes like Z-depth, etc... I understand what they do, but as I mentioned...in the past I so often destroyed pictures‘ natural look in post, just to return to the original plus a bit of curves, sharpness in the focus, a bit of desaturation and basics like these... :)))
Honestly, in a lot of tutorials or archviz-articles you see all kind of post-processing wizards... and the „final“ images look somehow „manipulated“ after post.
Long talk short: did you switch off all passes and try how the render / RAM behaves then?