More data, but OP is right on the weaknesses of the study—the author posted here [0] and acknowledged that they can't actually say anything about causality, just that 2023 looked different than 2020.

[0] https://news.ycombinator.com/item?id=39168841

I did, that's where my quote is from. The appendix confirms; they ran the regressions on just two inputs: 2022 and 2023 totals.