The best one is the one that you can stick to. Some people struggle with fasting, some people struggle with keto. One restricts your eating time, the other restricts what you can eat. You can even combine the two in a single plan.
Fasting is going to be better for autophagy.
I can only speak about which is better for my body - and it’s definitely long-term fasting (as in fasting as a lifestyle; high frequency, not the same as regular extended fasts).
Spending all day eating, digesting, and fussing about what to eat next is a recipe for misery. But that’s just me!