> Though I'd love to hear if people know how to do this stuff on iPhones

Very little in the realm of "server" or "raspberry pi alternative" could be done with modern iPhones despite even a 2-year old iphone being OP in terms of hardware for most home server tasks. They really work hard to prevent any use besides what's officially blessed by Tim Apple himself. Whether that's "for your own good" or not is a matter of opinion, I happen to think it's lame but don't want to debate it.