Yep extremely tiring. I'm an electronics engineer and work with audio signal processing for a living, and I've posted all sorts of technical analysis in the past on this forum and others. Back in the days of the CD player bit wars, I was involved in studies of this sort of thing that were commissioned for no other reason than to convince non-technical (or semi-technical) purchasing people that we could (or couldn't) use a different component in a properly designed system with no audible effects that might have somehow escaped our circuit modelling or physical test systems.
The only problems we found were when a circuit was poorly designed, or other circuits (sample and hold, RF, power coupling, etc). In guitar circuits, the biggest measurable effect might by ESR or leakage. And those are easily compensated for with parallel or series resistance on a decent ceramic or poly cap - and almost always are more easily compensated by turning a knob a few degrees. That's ignoring the effect that temperature has on the rest of a typical guitar circuit. In the end, any effects that might be audible in a guitar tone cap are swamped by other variables in the system. Dynamic absorption and other non-linearities and so far below the thermal noise in a guitar tone circuit that it is laughable to even consider them.
The biggest issue is when people conflate knowledge from different domains. Ie. radio frequency, power, high impedance/low impedance, instrumentation, etc. This is rampant in marketing (and therefore consumer misunderstanding), specifically in other areas like audio interconnect/speaker/power supply/guitar cabling, power amplifiers, pre-amplifiers, DACs, speakers, etc.
What’s relevant and factual is that different types of capacitors measure differently. People say, if it’s audible, it’s measurable and the inverse of that is if it’s got a measurable difference it should be audible. Unlike you, I don’t have to speculate about whether the differences in capacitors are great enough to be audible. I’ve listened and they are, so your conclusions are wrong.
Further, no one has stated any particular causation, simply that different capacitors can sound different and it could be any combination of reasons.
So, you are free to use your imagination as you have been doing and run through every unsubstantiated straw man you can dream up or you can deal with reality, that everything sounds different to some degree and not everyone is going to hear them at the same time.
It is possible that capacitors sound different in guitars, but you cannot hear the difference in whatever context you listen. Have you thought of that as a possible explanation given your exhaustive research into human fallibility?