the amount of gas going back into the action shouldn't affect the accuracy or pressure behind the bullet as it is leaving the gun. Have you tried a heavier buffer and spring? Could help with the over gassing before you messing around with an adj. gas block.
If money is no object, KAC. If you are looking for an excellent rifle with a great value, wait for this to come back in stock:
https://www.familyfirearms.com/product/daniel-defense-ddm4-v7-16-32rd-exclusive-w-geissele-ssa-trigger-magpul-mbus-pro-sights-ergo-rail-panels-webgb-1122-2
People like the raptor. Blem can be found pretty cheap here https://tacticalsurplususa.com/radian-raptor-chrg-hndl-556-blk-blem/
This is a good deal on the aero breach if you need a bcg...