thanks for pointing out, this way works fine:
[wasabis3]
type = s3
provider = Wasabi
env_auth = false
access_key_id = BXXXXXXXXX
secret_access_key = eZZZZZZZZZZ
endpoint = s3.eu-central-1.wasabisys.com
chunk_size = 24M
upload_concurrency = 8
For the Documentation section, it still confuses me and I guess not only me.