To be very blunt, I don’t think there is any sort of EC formula the most selective colleges are looking for, and I think attempts to follow the sorts of formulas that are typically passed around by peers and families on and off social media are more likely to actually be counterproductive than helpful. Instead, your best bet is to do a small handful of things you truly enjoy and/or find very meaningful, with energy and dedication.
Indeed, the whole idea of turning the concept of a “passion project” into a formulaic box to check is on some level truly absurd. The original point was supposed to be if you ARE really passionate about something but there are not pre-existing activities at your school or in your community conducive to acting on that passion, then you can do something self-designed instead. But then some people turned that into the idea that you should start with the goal of doing a “passion project” because it will look good to colleges, and then you get a bunch of kids asking other kids what to do for a passion project because they are not really passionate about anything suitable.
OK, so the helpful understanding is you have all sorts of different options for how to spend your non-academic time depending on what you truly find enjoyable and meaningful. But you should be choosing among those many things based on what you truly find enjoyable and meaningful, not because you heard they will look good to colleges.
I would also distinguish the very most selective colleges from other very selective, but not that selective, colleges.
Like, suppose your passion is a performing art, and you are applying with that as your main EC, implicitly suggesting you will want to continue that at a high level in college–maybe not a major, but maybe a minor and wanting to participate in the top level activities at that college.
Well, at many Ivies, the truth is the kids who end up doing that stuff have like conservatory-level talent/ability. So it might be a problem trying to get into Yale, say, as a performing arts kids if you are not actually at that level.
But very quickly that sort of thing fades, and many excellent research universities and liberal arts colleges and so on might be perfectly happy to just see you have a normal amount of talent for your performing art.
And again, the problem is people see this and then start trying to kill themselves to reach that level of accomplishment in something, anything, to try to get into a college like Yale. And maybe it will work, but maybe it won’t, because it is truly hard to do that, and most smart, hard-working, talented kids who try fail anyway.
So the far healthier thing to do is again just do what you really enjoy and find meaningful with energy and dedication. If you end up one of those rare talents, maybe it will help you get into a Yale. If not, but you still do reasonably well, maybe it will help you get into a Georgetown. Or so on. But regardless, you will have a great childhood and then go to a great college, which should be the goal.