On the play time window** thing , another tactic which can work (and worked well for me back when I was active) is if you have a climax or a major meta plot running, break it out into multiple components. The three ring circus narrative like you get pretty commonly, but is executed really well in Return of the Jedi.
You have the attack on the forest moon to disable the shields so the ships can attack, and of course you have the climactic battle in the Throne Room. Reproduced well in The Phantom Menace as well.
Break up whatever your “climax” is into multiple components and have those stories get divvied up in different time zones.
It’s not always going to be perfect either because you are shoehorning players into a scene based around their playing time window instead of natural compatibilities, but you can absolutely structure things in that way - have a plan of attack that requires some other critical task occur before hand, schedule that during the “prime play” window of the folks who tend to play in the Australia/Asian window (12 hours or so ahead of US), and then another for Europe, etc.
And then, if you want to be really ambitious, make all of those critical components RPed live to the conclusion, and play that one async (or as Coin suggested, throw up a vignette scene for everything to write their own aftermath conclusion).
I had some good success with that in the past, but it does require having someone willing to ST in each of those time periods, or letting players free from on their own (which I am not generally opposed to either.)
**It’s not precisely timezone because you may have someone who works overnight in THEIR timezome so aligns better with another timezone.