See, what you are doing is pointing at the noise instead of looking at the signal. The problems you flag are not fatal, because we can readily identify possible causes for the mismatches even if we don’t have all the details in place. You have already been told that the C14 measurements in diamond are meaningless because they are less than the laboratory blank. Will you now drop that ‘problem’?
On the other hand, you are simply ignoring the signal present in thousands of statistically strongly correlated datings. You have no idea of how the datapoints could possibly still line up if the model asumptions would be wrong.
Let me tell you this: accelerated nuclear decay will not help you, because (apart from all other considerations, such as compete lack of empirical evidence for such variations existing in the conditions where rocks are formed) the variations would have to be exactly fine-tuned with each individual analysis to still make the data points line up.
Remember, in your YEC model the data in an isochrone plot ought to pretty much still fall on the original horizontal line (there won’t be isotope differentiation at the scale of crystallisation of a hand-sized sample, and in 6000 years the isochron would barely rotate away from the horizontal).
A uniform accelerated decay across the globe would make all lines rotate by the same amount, because they are all equally old. So, every isochrone we find anywhere should be at the same angle. Yet, in reality we see isochrones at all angles corresponding to ages across 6 orders of magnitude, depending on which rocks we sample. So, the decay would have to vary from place to place by 6 orders of magnitude, but the variation would also have to be slow enough that samples from associated nearby rock units would still show the same angle (remember the French granite? Isochrons with the same angle from associated samples several kilometers apart).
Yet, when we then sample nearby but geologically different rock suites that, according to us, are of markedly different ages, all of a sudden the decay rate acceleration would have to be markedly different there, so that their isochron comes in at the different angle that we see. In other words, the decay rate acceleration would have to show a strong correlation with rock type.
Tell me, how do Rb atoms know in what type of rock they are incorporated, so that they can finetune their decay so as to a) still fall on a straight line, but b) at the same time fall on a different straight line than the Rb atoms in a nearby but different rock type?
This does not make any sense.
It is actually even worse. The decay rates of different decays systems would have to vary in such a way that their isochrones would still overlie each other (as they often do). How do U atoms know at what rate to decay so that their isochrone ends up at the same angle as the isochron of nearby Rb atoms in the same sample?
On top of all this, all of these thousands of necessary extremely finetuned decay rate variations for which there is precisely zero evidence, you are also facing the unfortunate truth that all of that radiation in such a short time would kill of whoever was unfortunate enough to be around at the time.