I believe the following to be the ideal Shimano 12 speed min/max optimized setup:
SLX crank arms + aftermarket oval ring
XTR shifter and XTR chain
XT cassette and XT derailleur
No joke, the bare SLX crank arms (no chain ring) weigh exactly the same as XT. The weight difference is all in the chain ring (which I don’t care as I run aftermarket oval rings)
I find the XTR chains last longer than XT or SLX and I appreciate the extra corrosion resistance that comes with the higher grade inner plate surface treatment.