Wow that Whonix is interesting, is it possible on iPads and iPhones?
It is not. It is strictly a computer setup. Don't want to get too off topic in here, but essentially, to become compromised utilizing Whonix, you would require cascading failures or specific nation state targeting. It's not the most modern and pretty setup, and it is a VM so it is good if your host system has some power, but it's far more secure than running a VPN on a desktop and a router. It is for a threat model more in line with what it sounds like you need, not the common person on here talking about VPN usage with Merlin.
I highly, highly recommend reading more into it. It will likely require some tradeoff and adjustment to what you do, but it is worth it.
And it should be understood that even with a VPN active, Mobile tech/communication is still predominantly insecure. The recent info about VPNs on iOS leaking a shirtload of data confirms that. Mobile usage should be kept to a literal minimum if possible, even with a VPN.