Authenticating with Google access token

Hi. I'm trying to perform authentication on GCP API Gateway using Google access token (ya29.***, OAuth2). However, the [the documentation](https://cloud.google.com/api-gateway/docs/authenticating-users-jwt) has content on only JWT tokens. It seems it is possible to use Google ID token (which is a JWT) but I don't have it. When I try to access token, it returns the following error:

"Jwt is not in the form of Header.Payload.Signature with two dots and 3 sections"

Is there any way to use Google access token with GCP API Gateway, or is it not possible at all?

Thank you