@creoleMalady This does not help you, but my setup works with MinIO S3 (current version minio_20220607003341.0.0_amd64.deb) and current XO commit a5e9f.
I'm running XO commit 379e4 (June 2nd) and it has been working correctly with Wasabi.
I updated XO to commit a5e9f (current master) on a second server and backup still works for me to MinIO.... Delta Backup as a full and as a delta with and without merge.