kalloc_type was really only the fist step, of a much larger protection.
We call it Memory Integrity Enforcement.
https://security.apple.com/blog/memory-integrity-enforcement/

Memory Integrity Enforcement: A complete vision for memory safety in Apple devices - Apple Security Research
Memory Integrity Enforcement (MIE) is the culmination of an unprecedented design and engineering effort spanning half a decade that combines the unique strengths of Apple silicon hardware with our advanced operating system security to provide industry-first, always-on memory safety protection across our devices — without compromising our best-in-class device performance. We believe Memory Integrity Enforcement represents the most significant upgrade to memory safety in the history of consumer operating systems.