...Damn, what if Enel got pushed off of Birka? We had Kaido introduced jumping off a Sky Island to his "Death", at Balloon Terminal: Balloons were big in Enel's Cover Series, because they're what Spacey and the other Automata used to fly up to the Moon.
Wait, Enel was born 39 years ago... he had to have destroyed it more recently, what timeline were you looking at?
Birka is also loosely connected to ELbaph through real life lore, I'm really thinking we'll see Enel in Elbaph sooner or later. But, like I've said, I think we'll leave Elbaph for Pluton, then return after Pluton is Activated.