I like how they call it a 'true' RNG... unless it's got a cesium core and a Geiger counter mounted on the USB, I'd hardly call it 'true' :). At best, it's good enough.
Shot noise, avalanche noise etc. are just as true. Even throwing a die would be in the same category.
Same principle would apply to all the other methods you mentioned since there's always a definite seed value, regardless of how difficult it is for you or another observer to capture it.
All the approaches you listed would result in quality pseudo-random numbers, however, a genuine random number at the source has no apparent cause or series of events leading up to it. Cesium is one such source of genuine, uninspired and uninfluenced source of randomness. Cosmic radiation is probably another although that's probably a lot harder to capture.
Here's a more detailed explanation of why radiation from radioactive decay is bona fide random.
https://www.symmetrymagazine.org/breaking/2009/03/30/real-ra...
https://engineering.mit.edu/engage/ask-an-engineer/can-a-com...
The NeuG is best described as a high quality PRNG as are most others unless they truly capture some random, cosmic phenomena, like echoes from the big bang detectable as cosmic background radiation.. Allegedly nothing tops the big bang as a random number generator.
Still no difference to shot noise or avalanche noise. You have a statistic that says how many electrons you exppect to see, but no foundational knowledge which electron will be seen at what point in time.
I find your point of view very esoteric.
There are many sources of truly random events (as in quantum), including tunneling in diodes.
Then there are chaotic systems which are good enough to be random. There, even in a deterministic universe (it doesn't appear to be) and given infinite amount of computational power (impossible), you'd still be unable predict the future (due to measurement error).
TRNG are hard to do correctly, but why are they limited to geiger counters and radioactive mtls? Is it because you can't "hack" the nuclear core (not exactly true, but sure)? Again that would be a doing the TRNG right, not a lack of randomness in physical systems.