My workout partner does keto - but she has thyroid problems and it apparently helps with that. I ran it for about 3 months last fall and saw fairly decent results. Soon as I ate about 50g of carbs I looked much more "full" and forgot about the glory of eating bread and tortillas. I'll probably never run it again - I never felt all that great while running it as opposed to just a standard cut with the normal variation of macros. Strength plummeted too.
Interesting, as you are supposed to have an initial drop in performance until "adaptation"
You didn't see the strength losses return 6 weeks into it?