" at least somewhere in the world; occurring over many many millions of years then this should be producing exceedingly vast amounts of opportunities for fossilization (literally, million
s)"
In reality, there actually are an uncountable number of fossils that have been found. Probably in the trillions, with millions recorded in publication.
However, these trillions are 99% marine (snail shells, clams, squid shells etc.). Simply because it is in the ocean where deposition occurs (and relatively rapid burial).
In contrast, T rex specimen, while popular, has only been discovered few enough times to be counted on ones fingers and toes. Because realistically, its not actually common for local flood waters to just bury an animal instantly beyond the point in which they were be exposed to predation and bacterial decomposition.
It should be noted that there are pockets where terrestrial fossils are found though, such as in areas of prehistoric swamps. Temporally along the K-T Iridium boundary, or along subsurface prehistoric streambeds, such as those depicted below.
Which is to be expected if uniformitarian views were correct. We should expect to see far more marine fossils given their depositional environment. If terrestrial fossils are found, it is no surprise that many would be in places of exceptionally rapid burial, such as in prehistoric peat bogs and swamps.
It also should not be of surprise to us, that dinosaur fossils do not appear after the K-T mesozoic to cenozoic boundary, as the K-T boundary consisting of iridium and being superpositionally aligned with the yucatan crater impact, suggests extinction by a massive asteroid.
Chicxulub crater - Wikipedia
If strata were all deposited by a global flood, then dinosaurs ought to be found in the cenozoic and in the paleozoic. But of the thousands of dinosaur fossils found, they are not ever found in the cenozoic or paleozoic (or even pre-cambrian), aside from maybe 1 or 2 pseudoscience hoax website examples with peoples hand prints inside the dinosaur footprints lol.
Does any young earther have an explanation for why there are no dinosaurs in the cenozoic or paleozoic? no of course not. At best, we are given a response of "well they couldnt run as fast as the cenozoic giant sloth, so they died in the flood before giant sloths did". And the famous "oh those scientists are just hiding fossils in their basements so they dont get fired from their jobs". Haha.
Then of course there is the hilarious discussion about seeded plants outrunning non-vascular plants.
There really is no question that uniformitarian views have greater explanatory power over young earth views, with respect to the fossil succession (by a long shot).