Bassbob
Emissary
No upgraded BCG provides upgraded performance no matter the cut. A BCG has no added function as to shooting suppressed vs unsuppressed, and any BCG stating otherwise is just a gimmick. Adding a new upper with a rail of some sort is considered an upgrade. A good barrel is probably your best upgrade on an AR an most firearms. Accurizing your upper receiver for the tightest barrel fit can be considered an upgrade. Making your firearm optics cut can be considered an upgrade, adding lightweight parts can be considered an upgrade, etc...etc...etc... I run almost every available finish on BCGs and I have a decent amount of experience with AR building and ownership and I've yet to find a BCG that was a performance upgrade and this includes shooting suppressed.
To resolve the blemish issues the OP is having with a firearm that he appreciates is, one of the proposed options to possibly upgrade to a new slide with an optics cut.
So a BCG with a Nickel Boron finish doesn't operate more smoothly than a phosphate BCG ?