In WordPress, I have to create a functionality like as below Without any plugin:

Create Two Buttons: One for Instagram login and another for TikTok login.

Redirect to OAuth Authentication: When a user clicks a button, redirect them to the respective OAuth URL.

Handle Authentication & Redirect Back: Once authenticated, users will be redirected back to your website with an access token.

Fetch User Data: Use the access token to retrieve follower count and basic user details. Save Data in User Meta: Store the retrieved information (followers, username, etc.) in WordPress user meta.