Cannot delete Gateway Load Balancer VPC Endpoint — requester-managed error

The issue you're experiencing is common when dealing with requester-managed VPC endpoints, which are created and managed by AWS services on your behalf. These endpoints cannot be deleted directly by users. To resolve this, you need to focus on removing the underlying AWS resource that created this endpoint, rather than trying to delete the endpoint itself.

In your case, the endpoint is associated with a Gateway Load Balancer. To remove this endpoint, you should:

1. Identify and delete the Gateway Load Balancer that is associated with this VPC endpoint. Look for Gateway Load Balancers in your account that might be using this endpoint.

2. After deleting the Gateway Load Balancer, wait for a few minutes. AWS should automatically clean up the requester-managed VPC endpoint and its associated network interfaces.

3. If you're still unable to delete the VPC or the endpoint after this, check for other AWS services that might be using the VPC or creating requester-managed resources.

4. Ensure that you've removed all dependencies on this endpoint in your VPC configuration, including any route table entries or security group rules that might reference it.

If you've followed these steps and are still unable to delete the endpoint, you may need to contact AWS Support for account-specific guidance. They can help identify any hidden dependencies in your setup or assist with removing the endpoint if it's truly orphaned.

Remember, the key to resolving this issue is to focus on removing the underlying service or resource that created the endpoint (in this case, the Gateway Load Balancer), rather than trying to delete the endpoint directly.

Sources
I can't delete endpoint, that was created by me previously | AWS re:Post
I cannot delete a VPC Endpoint | AWS re:Post
Can not delete VPC. Endpoint does not exist. | AWS re:Post