This is a good subject, I had some issues developing a simple infinity jump game.
Even running on browser (PC) it was not smooth, fps were not 'fixed'. First I thought that the problem was on my sprites and changed the whole project from 1080 to SD, for my surprise I kept with bad fps.
And, why? Why?? My project had about 120 events, not many..
So, I did the whole project again with event optimizations, I got a big difference in performance.
Should be nice to have a documentation with examples of good practices, showing where and how it affects in both cases, also should be nice to have a graphic showing which event is using more resources and how many times it triggered and when..
Know what I mean?