While bullet setback may be an issue with all semiautomatic pistols, my testing is specific to the P365/X/XL. My testing results may not apply to a different semiautomatic pistol.This isn't a "365" problem, it's an auto pistol issue well recognized over decades.
The test data speaks for itself. People may interpret, use it or not, as they wish. I actually started this discussion because someone was claiming that using the Makershot magazine loader could cause bullet setback. I've just loaded 5 different types of ammo with the Makershot loader with no signs whatsoever that it caused any bullet setback. If a problem exists I want to know what the root cause or causes of the problem are. I often need to do my own testing to find the answers.
I still don't have any authoritative answer as to how serious the bullet setback issue is for a P365/X/XL. Even if knew that bullet setback isn't a safety issue, I still don't know how seriously it affects accuracy.