I am in a bunch of facebook groups as well, and I haven’t seen anyone attempt to use pellets for pizza, but I have seen people build wood fires to get their oven heated up, and then once it starts to cool to smoking temperature, they then use the pellet tubes to smoke inside of their ovens. I use a pellet tube inside of my pellet grill as well when doing pork butts and large meats since the pellet grills don’t provide alot of smoke.
As for charcoal, I have seen others try to cook with it inside of ovens, and they find out that coal does produce alot of heat but if you think of old time blacksmiths, they constantly had to utilize bellows to provide additional airflow. I have seen some rig up fans as well, but overall like biker matt said, most coal fire ovens work in a different fashion.
Regardless, what I do know, is the drier the wood, the better for heat and hardwoods. I wouldn’t use pine or anything that will add sap or pressure treated for sure. Soft woods are sometimes good at the start to get the fire started, but dry hardwoods are better. Some are easier to find than others depending on your area. See attached chart that shows wood in a fireplace, but you can see which woods are good to use in oven in the States.
