Provide some evidence that 10,000 rolls as opposed to a few hundred would be necessary to identify such a pattern. Either find multiple sources that support your claim or fit the data given by Niara and show that a horizontal line (pure random) is equally a good a fit as a sine wave. ~500 rolls is enough to statistically determine that a d20 rng is producing non-uniform results (it can detect even a single number appearing too frequently or not enough), so it should also be good enough to detect a pattern in the rolls. In fact, you should need less data points to detect a pattern because you're adding extra information: the order of rolls.

You require evidence that large amounts of data allow folks to better assess the significance of the data and avoid errors from testing a small number of possibly atypical samples?

I can point you to any statistic course ever.

I also recommend you look up apophenia.

Apophenia is the tendency to perceive meaningful connections between unrelated things

Otherwise, I'm going to accept all the sources I've found that claim that a few hundred rolls is sufficient for a good sample size.

Again, a few hundred rolls is sufficient for determining the average value (85% confidence), not for finding significant patterns within data. (Of course the data does show that BG3 averages are random (85% confidence), but please don't let facts get in your way.

The clear pattern in Niara's data, combined with my analysis of 508 unweighted rolls and 750 weighted rolls, show that Larian's unweighted rng is not uniform and produces an overabundance of '17's and underabundances of '1's and '6's.

As I've stated you are free to you make up conspiracy theories based on insufficient data and imagined patterns.

Seems to be a popular activity in the world these days.