Its a balance thats always tricky. While I see your point and also want to keep to the highest standard.
The reality is is that you shut out the majority of people with this mindset, especially outside the USA where iphone usage is way lower.
Only providing info for folks already on those platforms does not seem to be the most productive stance.
What if we provide a guide explaining how one can use the private space if you are on a platform that supports it, and point to alternatives if you are unfortunately still on older platforms. We could always remove the recommendation for shelter once the android versions without private space are end of life.