I can now answer my own question. After a few months on the keto diet, I have appareantly become fat-adapted and don't need carbs to ride like I once did. I did 83 miles over the weekend in a fairly low carb state and didn't bonk or need sugar to keep pedaling.

There was one several mile section directly into a headwind with no breaks and I thought for sure I'd feel my energy wane or have a bonk during or after, but I did not. My energy level stayed the same through the whole ride. Felt perfectly fine after as well, not a hint of fatigue. I knew something had changed at that point. I don't think I have the explosive energy I had when I was running on sugar, but my endurance seems to be increasing.

It just takes time for your body to adjust to running on ketones/fat versus sugar. I've also dropped 21 lbs. since I started and my blood work looks great according to my doctor.