I did contact the support of the the kodi remote app Yatse, if it would be possible to purchase the pro version without using the Play Store. Here is the answer:

You can purchase the pro version via paypal from https://yatse.tv/yatse-payment-troubleshooting it's tied to an email account present in the OS / settings of your device and does not need to be google one. The Pro version will only work on Android devices where this email is registered as an Android account.

Since there is no email account connected with the OS, I think it is not possible to go this way, is it?

    dirksche

    As far as I know it should work as expected. They have their own forum here: https://community.yatse.tv/. People on the forum say they're running OSs without Google Play, and instead they have microG.

    Their dev says the account must be listed in Settings > Passwords & accounts.

    Other than that, who knows? Pretty sure GrapheneOS hasn't made any changes to that part of AOSP, so if it works on other phones it will most likely work on GrapheneOS. It seems like they're helpful when users run into issues, so if you pay for the app I think they'll help you out via email or on their forum.

      unwat Thanks for your assessment. I will give it a try. If it woun't work I will see the 3,99€ as a donation.

      5 days later

      It's 4,75 € and it works. The pro-version is now running on my GOS.