SO!
I can actually explain this as a noted Vong writer.
It's important to note anything force-dead in general tends to be very much focused/fixated around the idea of being unable to personally interact with the force (aka, they do not have a connection to the living energy field that binds all beings). This is why Omni in the vong books is a big deal - he's the only vong to gain force sensitivity via shaping yammosk tissue into his brain. As for how it works with the vong, direct force powers do not work, but stuff like lightning or throwing rocks at them still works. This is because it's not interacting with the vong directly, but generating energy that isn't inherently force-attuned/force-based and/or using the environment.
Also, to explain vongsense, it's not sensing the vong directly. It's sensing the absence of a presence. Like how you view the cut-out of an outline, but can't see the actual cut-out image. basically that.
but yeah, vong are pretty cool and underrated imho, force-dead species can work if people keep in account that they are not just a classic "lol the vong are like flat immune to everything" misconception. There's times where the vong straight up just get merked by force rocky to the face. it's doable.
Also, wounds in the force =/= force dead. It's just being a edgelord who extrudes edge and fucked-up "haha look at me i'm scary". Nihilus a poser fr.
But yeah, this hopefully explains force dead stuff a bit.