I've benchmarked R2 and S3 and S3 is well ahead in terms of latency especially on ListObject requests. I think R2 has come kind of concurrency limit as concurrent ListObject requests seem to to have increase failure rate when serving simultaneous requests

I have a few of the S3-like wired up live over the internet you can try yourself in your browser. Backblaze is surprisingly performant which I did not expect (S3 is still king though)

https://observablehq.com/@tomlarkworthy/mps3-vendor-examples