At the end of the day, regardless of how much planning and hard work goes into it, kids ultimately are who they are. If it requires an unnatural amount of work, dedication (I mean this literally - work that is not natural for the kid). then they likely won’t and shouldn’t get in to that set of X schools. They also likely wouldn’t be happy in that environment.
I think it’s sad when so much emphasis is put on getting in to that specific school (s), so ECs are planned, classes are planned, volunteer work is planned to create the veneer that that is representative of the kid. If s/he would normally participate in those activities, great. If not, you’re kidding yourself. You can’t maintain that facade long term, nor would you want to. Aim for schools that fit who you are or want to aspire to be. But be genuine about it.