It seems people have pretty individualized responses to this. In general, the research shows decreases in performance except for endurance events. Personally, I found my recovery was great on keto. Better than normal even. I was doing a strength cycle so my weights were increasing at the time and I was getting stronger. I actually felt better in the gym, and I lift pretty heavy. A lot of the aches and pains in my joints seemed to go away. Downsides: my gut felt weird, and you have work hard at getting adequate fiber and stuff. Also, it's hard to eat socially.

I was eating a higher protein diet than usually considered keto, but urinalysis confirmed ketosis.