Energy crashes often come from things way simpler than diet - I've noticed on my morning runs that I feel way different depending on how much I'm actually moving and sleeping, and when I was stuck working from home full-time I felt the same drain you're describing until I got back into a routine. A carnivore diet might work short-term because cutting out processed junk usually does give people a boost, but extreme restriction tends to catch up with you eventually, and you're missing whole food groups your body actually needs. Before overhauling everything, try the basics first: get outside more, move regularly, make sure you're sleeping enough, and eat actual whole foods (meat, veggies, whatever) without going all-in on something extreme. If you're still dragging after a few weeks of that, it's worth talking to a doctor because fatigue can signal something else going on.