It looks similar to minio, which as also an AGPL single binary that implements the S3 API. However Minio is written in Go and Garage is in Rust. I'd love to see a detailed comparison.

Seaweed design goals / features: https://github.com/seaweedfs/seaweedfs

MinIO: https://min.io/docs/minio/linux/operations/concepts.html

Note Garage list of non goals specify priority features of Seaweed or MinIO, for example erasure coding.