Q - Can I show third party login flows like google, Facebook login ?
No, PhonePe expects merchants to not show any third party login page or banners in microApp.

Q - What is the expected behavior when a user revisits the merchant InApp through PhonePe after giving consent the first time, do we ask the consent again?

The user is asked for the consent only once. If he uninstalls or deletes the cache, the consent is asked again.

Q - Who will show user consent page to the user ?
PhonePe will show the user consent screen for PWA integration

Q - What happens if the user denies the consent ?
User can browse through the micro app but needs to accept the consent to do payment

Q - Getting error code "ENTITY_NOT_FOUND" in the "https://apps-uat.phonepe.com/v3/service/auth/access" API ?

The grant token send in the above API expires in 600 seconds. ENTITY_NOT_FOUND means that the grant token has expired. Please generate a new grant token to get the access token.