If you have root access you can try editing UserCustom.ini and locking it with chattr (might adb shell also usable)
I have not tried this way before, but this way the game will not able to write to this file so whatever you set will remain persist.
You can check /system/etc/init.sh to review how kernel command line parameters handled.
VULKAN=1 is does not exist anymore, using it does nothing.
FFMPEG_PREFER_C2 does not exist as well as VULKAN=1
GRALLOC4_MINIGBM=1 is correct one.