For OAuth I have been using Pathfix.com (they are leader for OAuth in Bubble) really simple if you have some API knowledge. Their support are great also. I have used this for Facebook login, LinkedIn Login and Instagram Login. Then once authentication is received back with the necessary tokens you can then allow the user to post photos, videos etc from your Adalo App onto the users own Pages/Profiles.
They are a NoCode Platform. But the only down side is it costs £. But it does work v well