For me, the two times I had to buy tires for an RV I just went to Discount Tire and bought whatever commercial highway tire was the cheapest.
Correct in buying commercial grade tires, ie: light truck type or better (heavy duty). By that I am talking about at least 10 ply tires! The weight of a motor home and it’s contents should be considered when buying tires! Buying just any old tire because your buddy recommended it is an accident waiting to happen!!