Vyvanse and Breakfast

So I am kind of new to taking Vyvanse. I used to take Adderall XR/Adderall but I wanted to see if it would work better for me. I’ve been reading lots of things about a high protein diet etc etc. I thought I had this figured out (I was drinking protein shakes or eating protein bars) but I saw something about avoiding dairy? Some of my shakes are “dairy-free” but they really aren’t since they contain milk-proteins. And I’m technically allergic to it. And then I read some articles about avoiding coffee/caffeine? Can anyone elaborate on these things a little for me because I am just sooooo confused now. Thank you 😊 (mainly is the dairy thing true/what’s up with caffeine/coffee/protein rich breakfast ideas that are easy).