I think it's (mostly) sufficient to have a regex on git change-set for "new" "malloc" "calloc" keywords to cut most of such stuff if you have such a policy.

Documentation / UT are harder to define (what is good documentation, is UT covering everything?), but usage of manual memory handling can be spotted relatively easy automatically. There can be some exceptions for 3rd party libs interaction if it's absolutely necessary but detecting such occurrences and keeping track of them is relatively easy.

See, already there you missed all the C language constructs that C++ is copy-paste compatible with, and should only be used inside unsafe code blocks.

Which in C++ good practices means type safe abstractions not exposing any kind of C style strings, arrays, casts, pointer arithmetic,....

Unfortunely still relatively rare, some of us when we were the C++ Striking Force in the 1990's Usenet flamewars already advocated for such practices, most of them already possible with C++ARM, no need for modern, post-modern, rococo, baroque or whatever C++ style is going on with C++26 now.