[bee_rider]

I think when you ask what the difference between two phrases is, people will really dig down to try and find a difference.

IMO in this context it is basically shorthand for “things I learned/lessons learned while tuning LLM…,” and either would be fine. It is sort of an informal list of stuff the author learned.

In my experience (nothing special, just another native speaker) “lessons from <event>” is the more typical American (at least) English phrase. But it is sort of close to “Lessons on.” “Lessons on” would imply more refined material that is more narrowly focused on teaching. So I wonder if the author decided they just didn’t want to worry about any confusion, or the possibility that they might misuse a phrase.