WOOOOOOOOOW, teh Broscience is heavy in this thread!
Now, I won't go through the effort and pull up studies, so just take it from me and more experienced lifters:
-Replenishing electrolytes DURING training is important and not redundant.
-Simple carbs and and fast-acting proteins like whey can be ingested during training without "drawing blood away from the muscles".
Solid foods and slow-digesting nutrients are a bad idea during and shortly before training, that is true.
-The insulin spike is real and substantial for growth.
OP, you can probably find tastier alternatives to dextrose in water. At the Oly gym I train, the guys swear by Malz Bier (malt beer).
Personally, I mix 2 parts whey with 1 part cocoa powder ( contains maltodextrin) and a pinch of sea salt for my work out fuel. Mixed in with cold water obviously, not milk.