The form I had in december measured in FTP I could never reach again until today. It's kinda funny. I think I am fitter now than I was in December, because I recover much better and can do longer rides without. But that's "feel". It doesn't show in numbers.
It will be interesting what numbers I will do this December. I am not sure how much "headroom" there is still left, given that heart frequency is a big limiter.