But I understand the point well.
Discord and SnapChat are available for iOS and Android.
With Discord being available as good as everywhere.
So using Android does not exclude you socially in my experience, here in Australia.
Similarly in Europe and the UK, the What’s App was hugely popular and the default cross platform messenger.
I don’t entirely believe the rhetoric around Green and Blue bubbles that the press repeat without any real evidence. :-)
The fact is if everyone else uses it, this precludes them from many normal interactions that get replaced by social media. It's a cultural thing as much as it is a personal thing. You will feel excluded if you don't use it, so unless everyone changes, it's hard for you to change. That takes a determination even many adults lack.
The harmful effects of social media are not eliminated by choosing not to participate. They have a cultural impact (both benefit and harm) that expands beyond an individuals choice. We should reconsider how to handle teenagers on social media as a society. Not just tell them to preclude themselves if it's harming them.