HOw to generate and validate sigV4

I am making an API call to S3 using boto3 with the following code, which is working as expected:

import boto3
boto3.set_stream_logger(name='botocore')

s3 = boto3.resource(
    's3',
    aws_access_key_id="aws_access_key_id",
    aws_secret_access_key="aws_secret_access_key",
    region_name="us-east-1", # Region name here that matches the endpoint
    endpoint_url="https://myendpoint" # Include your namespace in the URL
)
  
# Print out the bucket names
for bucket in s3.buckets.all():
    print(bucket.name)

The above code, when executed is generating an Authorization header. My use case requires manually generating the Authorization header using the boto3 library to ensure it matches the one generated by the above code. However, due to some misconfiguration, they are not matching.

I am seeking guidance on how to manually generate the Authorization header using the boto3 library. Here is my code to generate the Authorization header:

import boto3
from botocore.auth import SigV4Auth
from botocore.awsrequest import AWSRequest
from botocore.credentials import Credentials

headers = {
    'Host': 'hostname',
    'x-amz-date': '20240703'   
    }

# Initialize the credentials and request
credentials = Credentials('accesskey', 'secret=')
request = AWSRequest(method='GET', url='https://myendpoint/', headers=headers)

# Sign the request
SigV4Auth(credentials, 's3', 'us-east-1').add_auth(request)
print(request.headers)