Any chance you have ADHD? I learned (far later in life than I would have liked) that I have ADHD and that it is one of the biggest reasons I'm almost always tired or even exhausted. Brain's just thinking too hard/inefficiently. (I have other contributing factors, but this one is significant and fairly obvious). Still can't get treatment, but the awareness has helped me work around it somewhat, by removing stressors and taking time to relax and/or hyperfocus.