aws-gate | Better AWS SSM Session manager CLI client | Identity Management library

This is my first project on AWS and I would appreciate it if someone can assist me with the AWS Cognito and google authentication. I am trying to authenticate users using their google email. Once the user's login using a web browser I receive an access token appended to the redirect URI as shown below. I am planning on retrieving the access code and then requesting an access token from AWS Cognito via AWS Lambda to allow users to make various API calls in AWS-Gateway.

I am struggling to extract the access token from the URL.

Redirect URL: https://test.execute-api.us-east-2.amazonaws.com/dev/?mytoken=

The URL after the user authenticates via google: https://test.execute-api.us-east-2.amazonaws.com/dev/?mytoken=#id_token=xyzzzzzzzzzzexpires_in=3600&token_type=Bearer

Things I already tried:

• Try to access code from URL query parameter in AWS gateway but since the URL contain pound sign I am not able to parse or access it as a query parameter in AWS lambda.
• Try accessing header in lambda function but access code is not passed as a header, it only appends to the path URL