AWS policy evaluation

I have an IAM role to be attached to a microservice in order to limit S3 folder access based on user-agent. The microservice parent account and the bucket owner are the same.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:*"
            ],
            "Resource": [
                "arn:aws:s3:::bucket-test/service/${aws:useragent}/*"
            ]
        },
        {
            "Sid": "AllowListingOfUserFolder",
            "Action": [
                "s3:ListBucket"
            ],
            "Effect": "Allow",
            "Resource": [
                "arn:aws:s3:::bucket-test"
            ],
            "Condition": {
                "StringLike": {
                    "s3:prefix": [
                        "service/${aws:useragent}/*"
                    ]
                }
            }
        }
    ]
}

The same S3 bucket has a default ACL where the account has R/W on objects and permissions.

Given the ACL and the IAM policy, I don't understand how this policy evaluates. For example, a user with the above role makes a put_object request to bucket-test/service/micro-b/new_object with user agent micro-a. Is this an explicit or implicit deny? Why?