I find it fascinating that a list of OSS/self-hosted S3 projects is on the front page of Hacker News. Familiar with most of these from working with on-premises customers with OpenFaaS. Minio was one of the first we integrated with in 2017 - back then it didn't support webhooks for notifications on object mutation, so ended up sending them a PR and showing it on the stage at Dockercon Austin.

I don't have a horse in this game, but have had pretty reasonable results using SeaweedFS for GitHub Actions caching. RustFS is on my list to test next, and a team mate is quite keen on Garage.