I take apart a LOT of drum brake set ups for the spindles. Many had the drums seized onto the shoes, etcc. rust, lack of rotation, etc.
I have a 3 pound hand sledge. Smack the drum where it goes from flat to down toward the backing plate. Focus on 1 area, and it will crack, and just move the impact point a little and soon the entire flat part will crack off. You can also hit it same place, and when it starts to crack, head toward the backing plate (but not all the way) and it will crack to the edge. Within 5 minutes, the drum will break up enough to come off.
If there are no fenders and you are accurate, you can use a full sized sledge, and in my experience, 5 or so so smacks and the drum will break up.
Based on condition, you need new ones anyway.
Once off, just smack the studs, and they will come off the hub, and the hub will separate from what is left of the drum, and you can then pull new studs into the hub. Sometimes the hub will pop off the drum with studs still on, so just put it in the vise, and finish punching out the studs.