Some thoughts:
Carbs/glucose are like a growth hormone/stimulant
They provide faster energy and cause things to grow faster than they would without them.
- Most cancers use glucose as energy.
- Muscles grow faster with glucose.
- Fat stores faster with glucose
Without them, you shouldn't have as much energy as you would with them - even on a ketogenic diet (unless you had some form of insulin resistance beforehand).
I do believe carbs had a purpose for us in nature but no where near the level available to us today.
A fresh kill would have likely had plenty of glucose available (from glycogen) to trigger insulin to fuel muscles and possibly store fat for a time when food would be limited (like winter).
The problem today with carbs is that there's too many in everything, including some of the veggies sold frequently in the USA.
The body probably runs best when kept at a low-ish body fat while spending most of it's time in ketosis.
Fat is more calorie dense so you don't need to consume as much in order to reach satiety and the most important vitamins are stored there. Less eating means more time for your body to allocate resources elsewhere.
But regardless of how much I think I know or how much humans in general think they know, we're probably still clueless about most stuff involving the body.
No matter if you choose keto, carnivore, vegan, or whatever WOE - try to do as much research as you can. Try to find as many people eating that diet as possible and learn about the good and the bad.
Ideally, the diet should not leave you deficient in any vitamins and you should feel continue to feel good for many years.
My belief is currently in carnivore but I haven't been doing it long enough to tell if it's the one for me (although some people have)
And don't be afraid to change your diet if it's not giving you the results you're looking for. Online, a lot of these diet communities are like cults - but at the core, we're all just trying to live longer and healthier lives.