Do you really need to use DME in your yeast starter? Can you use corn or cane sugar instead?
No you don’t want to use simple sugars. It can actually make the yeast lazy by consuming simple sugars. In addition I don’t think you get the yeast to multiply.
I could be wrong but I would think you would want to prepare your yeast by using a medium similar to the beer you are going to brew. It would be like having a pro nfl team practice against high schools and expecting them to then compete against other pro teams.