My links do not mention shielding being snake oil for a reason. Shielding isn't snake oil; it actually works, which you know as an IT engineer. You'll also know that you don't need STP cable for every install because it just doesn't make sense. You're not going to get a whole lot of EM or RF interference in say, a corporate office or home environment. Plus, you'd ideally want to ground the STP (otherwise, why bother?). Throughout my workplace, for example, it's UTP all the way. In your location, it might be different and you need that STP. Related, but irrelevant question: for what instances would soldering be utilized on an STP network cable? What's the use case there?
Still, that wasn't my point in talking about snake oil: I'm talking about audio cables. My apologies if this was not clear. Let's get back on track. Let's take these Linsoul adapters here. I stand by my opinion that it's snake oil for these to have shielding. I don't believe there's any tangible benefit. (I include headphone and IEM cables in this as well.)
I agree that many devices, particularly mobile communication devices and audio players (portable and desktop) emit some form of electromagnetic interference. I mention these relevant electronics because they're what this adapter is going to plug into.
So let me ask this: how much strength from what distance is that signal going to need to interfere with this Linsoul cable, which we'll call ,10 meter or 4 inches. You're going to have to show me the math that a smartphone or audio player (portable or desktop) is capable of putting out the kind of signal that would audibly interfere with this cable.
Show me your reasoning and sources, I'll admit you're right and maybe learn a thing in the process.
While we're still on the topic, I don't think shielding on a ,10 meter $25 IEM adapter is a particularly realistic expectation. Your questioning the lack of sheath/jacket is much more apropos.