Mine is performant. People sometimes use it as a synonym for high performance when really it just means working about as well as you would expect it to. It doesn't imply anything especially great.

There has only been one company I've worked for where 'learnings' was used extensively. It was Swedish. Not sure if that is relevant.

This is one of the very few that I'm a little -- a little! -- sympathetic toward. I don't know its origins, but to me, "lessons" can sound kind of harsh, like in the sense of a parent wagging their finger at a child, "I hope you've learned your lesson!" In contrast, "learnings" sounds quite a lot more friendly and less charged.