Would be great to have Sign in with Apple added to the list of social identity providers in Cloudflare Access.
That sure sounds appealing to me, though I suspect there are technical limitations to this, such as the strong dependency on your real email address. Any time you email Support, it needs to come from the email address tied to your account. So aliases don’t work (which is why I had to change mine at one point).
Does that support OAUTH or SAML? Then Generic OIDC provider will work.
Otherwise you might encourage Apple to support some kind of industry standard.