Registering twitter webhook on AWS API Gateway

Question

I'm trying to register a Twitter webhook on an API I create on AWS API Gateway. I was able to set up the CRC portion which provides the appropriate response through a browser however I'm unable to make post requests to the same endpoint. I've been following multiple guides on this including this and this

The code is below that is giving a 403 response:

from urllib.parse import quote_plus
from requests_oauthlib import OAuth1Session
import json
import tweepy
import urllib

CONSUMER_KEY = 'xxxxxxxxxxxxx'
CONSUMER_SECRET = 'xxxxxxxxxxxxx'
ACCESS_TOKEN = 'xxxxxxxxxxxxx'
ACCESS_SECRET = 'xxxxxxxxxxxxx'

twitter = OAuth1Session(CONSUMER_KEY,
                        client_secret=CONSUMER_SECRET,
                        resource_owner_key=ACCESS_TOKEN,
                        resource_owner_secret=ACCESS_SECRET)


webhook_endpoint = urllib.parse.quote_plus("https://#######.execute-api.us-east-2.amazonaws.com/dev/webhook")


url = 'https://api.twitter.com/1.1/account_activity/all/:env_name/' 


def register_webhook(url,twitter,webhook_endpoint):
    url+=f'webhooks.json?url={webhook_endpoint}'
    response = twitter.post(url)
    print(response)

def subscribe_to_user_activity(url,twitter):
    url+=f'subscriptions.json'
    response = twitter.post(url)
    print(response)


if __name__ == '__main__':
    register_webhook(url,twitter,webhook_endpoint)
    subscribe_to_user_activity(url,twitter)```
A couple of things I checked:

I can verify that the account is approved for account activity API, I created and counter checked the dev environment label, Keys were regenerated twice, Testing on Postman as advised here is giving a 200 forbidden response and doesn't work

In postman, I selected Oauth1.0 as the auth type and fill in Consumer Key, Consumer Secret, Access Token, Token Secret values, and provided the URL endpoint in the body. Is the POST request being sent to https://api.twitter.com/1.1/account_activity/all/:my_env_name/webhooks.json?

On the AWS side, the POST method was created on the resource with all default values

Any idea where I could be going wrong? Or a foolproof method of registering a Twitter webhook with AWS API gateway as the listener?