With the potatoes if you are using raw cook them half way then put them in a bath of salt mostly water and a little white or apple cider vinegar for just a family you should be ready to drain and fry within twenty minutes and they will come out restaurant steakhouse style

Chef here and I think I can explain what happened and what to do next time IT looks like you prepared everything at the same time and started cooking all together so it would come out hot without blanching the potatoes before cooking and good meat like that can make amazing burgers BUT you have to remember how much more of good fat is in it over chuck meat PERSONALLY at my restaurant I do a pan hot then put the patty in and flip around when you have a good crust to keep it the juices in THEN finish in a oven till the desired cooked level