Android has free and open artificial pancreas that is still easy to install and keeps us with complex type 1 diabetes alive.

Google may just want to kill us and Apple don't even let this kind of software exist without massive hurdles...

Because it's much worse (for me).

However at this point, as a GrapheneOS user if I couldn't use it for any reason I'll go to iOS (even though I used it for a couple of years and I've been fed up).

Because it still allows installing apps with some hoops, and iOS doesn't allow it at all.

Because (1) you'd be rewarding the entity that originated and normalized the loss of freedom that Google much later adopted, and (2) as Apple restricts more freedoms you'll still be able to enjoy them on Android for a few more years as Google remains (comparatively) more user friendly.