Regarding "that almost nobody on Earth fully understands anymore", I claim this is nonsense, and definitely not an obstacle.

I've audited codebases in languages that I haven't programmed in. It is a matter of grasping a few basic concepts, like branch execution, branch destination, where data is stored, how it is communicated. Don Lancaster told us how to do this: https://www.tinaja.com/ebooks/enhance_vI.pdf.