MinIO intentionally does not support DNS-style buckets. Adding DNS records and reconfiguring the reverse proxy to pass the DNS names through to MinIO didn’t help me, unfortunately. The only thing that helped was to downgrade to 1.16.16.
Note that while Amazon has deprecated path-style buckets, they have revised their original plan and will continue to support them for any buckets created prior to sunset in September 2020. It stands to reason that the SDK will continue to support these indefinitely. Could we have an option to specify whether to use path-style or DNS-style buckets, at least on S3-compatible storage?