I don’t respond to stimulants properly, and they don’t behave as intended (especially when taking SSRI’s).

I’ve been taking Adderall XR for many months now, but the first ADHD stimulant I had tried was Vyvanse. I can feel the medication kick in and start working. Compared to my baseline state, it’s quite a stark contrast. It’s lifts me out of dysfunction and chronic brain fog. I’m usually VERY sleepy and tired throughout the day, but when Adderall kicks in, I feel normal. Not euphoric, not elevated - just a normal functioning human being. I can complete tasks, listen, focus, and generally become a better version of myself while retaining all of the good qualities that make me, well, me. I’m currently taking a serotonin modulator (Trintellix) and am trying my very best to taper off. I believe this medication is making me unbearably fatigued and tired day-to-day, and therefore Adderall can’t work effectively. It also affects my memory, processing speed, and cognition in general. It almost feels like the stimulant medication can’t properly absorb with Trintellix in my system. I’ve tried taking 50 mg of Adderall, with such a high dose, you’d expect anxiety or physical symptoms, right? In fact, it’s quite the opposite. I feel calm initially, and then underlying fatigue hits me like a truck. I’ve tried every dose, and inevitably, it nearly puts me to sleep without fail after a few hours. Possible explanations: 1. My SSRI-like medication interacts with Adderall and renders it ineffective 2. I’m an ultra-rapid metabolizer 3. I’m chronically sleep deprived I’m so confused and perplexed. Thoughts?