Geese are stupidly tough and stay out of range for the shotguns in most setups. They need there own shot. Consider them class 1.5 and add shot specifically for large birds, something common irl and generally written into the regulations for waterfowl hunting.
Steel shot is avaliable for all shotgun gauges and most are loaded specifically with geese and larger birds in mind. This means much larger individual pellets and higher speeds than traditional lead shot loads. Of course these shells come with higher recoil but that's to be expected.
Steel shot, BB size, has a greater effective range and penetration compared to regular lead shot (which is largely illegal for waterfowl in general) at the cost of a higher price and more recoil.
Please make this shot type available