Normally Premiere allocates as much Ram as possible to to parallelize as much as possible (there is a setting for that. So that is not necessarily a bad thing. Well, it shouldn't crash of course.
I still recommend using CRF. High bitrate doesn't relate to a high visual qualitym a low quantizer value does.
In your case the first pass was fine.
Thx , I will give it a try. Maybe I will find somthing new~