We have never used a steamer for wallpaper removal. We’ve had great success with the paper tiger wall paper perforator tool and spray on wallpaper remover products similar to these seen below.
I just removed a whole room of wallpaper that had been up about 30 years! I scored it (not too deep so you don't ruin the plaster underneath) and then wet it with hot water with white vinegar in it. It came off in pieces and left some backing, but I just kept wetting what was left and it all came off. The biggest necessary ingredients...patience, determination and endurance! Good luck!
Best Way to Remove Wallpaper