Policy for highscores
Hi Lars, thanks for writing. You must definitely insert Scoreoid in your privacy policy, but since the service seems to just be a backend tool and not a third party service the users are subscribing to, you should be safe with the privacy policy addition and nothing else.
As of the actual addition, I suggest you to use our "Create custom service" button to add a few lines where you explain that your leaderboards are powered by Scoreoid, with a link to their privacy policy.
As of covering all the apps developed by your studio, you might also want to check our monthly pricing for multiple licenses: https://www.iubenda.com/en/pricing
Andrea