from my experiences

rustfs have promise, supports a lot of features, even allows to bring your own secret/access keys (if you want to migrate without changing creds on clients) but it's very much still in-development; and they have already prepared for bait-and-switch in code ( https://github.com/rustfs/rustfs/blob/main/rustfs/src/licens... )

Ceph is closest feature wise to actual S3 feature-set wise but it's a lot to setup. It pretty much wants few local servers, you can replicate to another site but each site on its own is pretty latency sensitive between storage servers. It also offers many other features aside, as S3 is just built on top of their object store that can be also used for VM storage or even FUSE-compatible FS

Garage is great but it is very much "just to store stuff", it lacks features on both S3 side (S3 have a bunch of advanced ACLs many of the alternatives don't support, and stuff for HTTP headers too) and management side (stuff like "allow access key to access only certain path on the bucket is impossible for example). Also the clustering feature is very WAN-aware, unlike ceph where you pretty much have to have all your storage servers in same rack if you want a single site to have replication.