While I do not have an answer to your question, I have the impression that most (or all) mineral based engine oils already contain some zinc additive.
Over the past 15 years with my 6.3 I have not used any such additional zinc additive but my mileage is relatively low, 1000-2000 km as yearly average.
109.018.12 1968 Bronze Braun (M100 in good shape)
126.039.1A 1988 Dunkelblau (M117 so a bit slower)
+ A few other MBs used for daily transport