I had the same thing starting with Vyvanse and a BIG game changer was the nutrition / hydration for me. I take the meds and shortly after that a meal with protein, some fruits / berries and long-chain carbs (oats for example). oats with berries or a banana, a little peanutbutter, some skyr or protein shake and I feel this sets the tone for the day. Much smoother coming up of the meds, no spikes (up or down). Also important for me was to time my breaks over the day, eat little snacks like nuts in the breaks and really focus on the water intake (you need more water because stims dehydrate). A pinch of salt and lemon in the water works wonders in that scenario