My sympathies. The short answer is you will not be able to reason with your parents. In the four years I’ve participated in this forum, I’ve seen many students in your situation. I don’t think I’ve seen one where the parents had a sudden change of mind and decided “any very good” university is good enough. Parents who think T30 enrollment is the only goal don’t easily change and say “Cal State X or Creighton U is good enough.”
My best suggestion for your sanity is to continue doing what you’re doing in school, try to do the ECs that make you happiest while not angering your parents, and try to add as many “other” schools to your application list that you can.
Explain to your parents about how rejective Stanford (and similar schools) really are. Explain that 95% of all applicants are denied enrollment. Explain to your parents that these other schools are backup plans in case the record high application statistics at Stanford work out negatively for your admission chances.
Don’t try to convince your parents to drop their obsession with high-ranked schools. Appeal to their good sense and logic by showing them you need a back-up list of schools so you can make a good choice if Stanford (and its ilk) do not admit you. Tell them you don’t want all your (and their) hard work to go to waste on a foolish “Stanford or nothing” plan. Tell them you’re not saying NO to Stanford - tell them you’re saying “if I don’t get in, let’s have some great options that aren’t in the top 50.”
You’ve done great so far. Keep up the fantastic work. Best of luck to you.