>> Interestingly, among these depictions there are some which indeed appear to be symbolic substitutes for more complex images, like the bucranium (ox head) in place of a full aurochs, or arrow-like zigzag lines representing snakes, and large birds reduced to a few characteristic lines. These depictions and their “abbreviations” seem to adhere to a certain convention, kind of a standardisation even, suggesting a communication system that uses these stone objects as media to store important information and knowledge.
>But totally not writing, yo.
Children drawings have the same characteristics but are not writings
Yes, and the final sentence "But in my humble opinion we’re not seeing phonetic values assigned to specific symbols representing spoken language here yet" is fair enough.
The letter A evolved from an ox head, but that's mere coincidence, showing only an enduring interest in symbols of ox heads.