We maintain a page that shows our compatibility with S3 API. It's at https://www.tigrisdata.com/docs/api/s3/. The test runner is open source at https://github.com/tigrisdata-community/s3-api-compat-tests
Also, none of them implement full S3 API and features.
Ceph certainly implements the full API spec, though it may lag behind some changes. It's mostly a question of engineering time available to the projects to keep up with changes.