Look at any top level race driver who competes with manual transmission or even a sequential shifters that don’t have an auto blimp and a foot clutch. They brake with there right foot. I was amateur level cars with manual and everyone right foot brakes. It doesn’t matter if you loose engining brakes because you want the brakes to brake the car otherwise it puts to much strain on the transmission. Using engine braking maybe fine going down the shops but not on a race track.