I've run some benchmarks a couple years ago, I don't have them at hand unfortunately but off the top of my mind, seqread 4k produced around 1500 IOPS while seqwrite was like a third of that. The practical performance was abysmal, I moved PostgreSQL storage to a volume and it was very noticeably slower just by browsing the web app (compared to NVMe SSD storage).

For comparison, I'm now using UpCloud which uses network-attached storage for all volumes and easily hits 10k IOPS (up to 100k with some tuning).

I certainly may have missed something while testing this so I'm happy if someone else wants to contribute and correct me if I'm wrong.