Errrrmmmm I think this is just an issue either with your choice of distro or your approach to security.
The Linux ecosystem has by far some of the greatest security technologies available for modern operating systems. Android is a Linux distribution after all.
Most of the issues with Linux on a phone so far is more the hardware and architecture to support and integrate the hardware.
Major mobile device manufacturers have secure enclaves, cryptographic co-processors, advanced face/depth cameras, fingerprint readers, etc. The system architecture needs to be tailored to the hardware and security architecture for the threat models mobile devices face that you want to mitigate.
iOS is Unix deep under the hood, Android is Linux deep under the hood. The issues here aren’t with the kernels, they’re with userspace, hardware selection, and perhaps the odd supporting driver, service, or interface.