I applied for Psychology and certificiates/minors in Entrepreneurship or something similar. I applied for International affairs at one of the ivies.
About grades. They aren’t just a raw performance measure; they reflect learning. So, while some grades might be a fluke or due to moving around (you had little control over this,) a tippy top reviewer may wonder whether you’re prepared for a college that’s highly competitive, once there. It’s also affected by how those B and C classes relate to the possible major.
Yes, these circumstances and a bang-up rest of the app package might (might) be viewed differently. Some cause or activity you pursued through all the school changes can show well. But it’s not quite “founding” something or fundraising. Right now, there’s too much we don’t know about you, your ECs, school support/LoRs, etc, to say more.
Also, we’d need to know more about the last school or two- any relationship they may have with any of your targets (someone to really go to bat for you, summarize the challenges but emphasizie your positives.) Or, whether this latest high school is, itself, rigorous. And where it is. (Some countries produce far more applicants than the college can pick. The tippy top US colleges tend to aim for geographic diversity among countries.)
So much of this is beyond your control. I agree your options include some less competitive colleges, maybe transferring after two years. Or focusing your high tier goals on possible grad programs.