Part of that may have to do with the work Taron Egerton put in with things like the stair scene and the portion of the movie where he had to figure out how to “sing” underwater with a camera trained on him.
A lot of the reason I personally enjoyed Rocketman was because Taron Egerton and Dexter Fletcher did a good job of making Elton John seem vulnerable and someone the audience can empathize with even at his lowest.