I can critique sumo way better than i can actually do it
You are basically just doing a modified conventional, you need to point your toes out more to start. The whole point of sumo is to shorten the ROM, having your feet like that isn't doing that, next you want to externally rotate your knees as much as possible, way easier said than done but imagine opening them up at the bottom of a squat, try do that. Next you want to sit back as much as possible and load the **** out of your hips and pull your self as tight as possible when you grab onto the bar. Some people like to look straight up and it helps keep the back really upright.
Watch this guy and try to imitate as much as possible, he is kinda tall as well but his form is damn near flawless.
And if you want to see the best on earth do it, I give you Yury Belkin, the all time world record holder at 220.