It’s not quite the same though. With a custom android ROM, you can be pretty confident that everything kernel-and-up is not spying on you. On iOS and macOS, you don’t have the same level of verifiability, as the OS could just circumvent any VPN/firewall you might have configured. They might pinky promise not to, but without running another external firewall it’s not really verifiable.
It’s not quite the same though. With a custom android ROM, you can be pretty confident that everything kernel-and-up is not spying on you. On iOS and macOS, you don’t have the same level of verifiability, as the OS could just circumvent any VPN/firewall you might have configured. They might pinky promise not to, but without running another external firewall it’s not really verifiable.