Hello,
I am using rom without google play store and play services.
I use grapheneos for security reason. it doesn’t support google play services.
I tried to download apk and install the app. and it doesn’t work since version 2.
I guess that is because of the payment functions.
I hope there is a way to use the application without play store.
Thanks 
We don’t offer our Android app outside Google Play. Sorry for the inconvenience.
If we get a lot of requests and if we find Google Play rules allow it we’ll consider adding an APK outside the store in the future. The important thing for us is to not break any Google/Android rules or policies.
I understand. Thank you for reply.
Okay,
There are lots of 3rd party websites where you can download applications. But still, there are lots of trust issues and security matters.
In that segment, I can help you, by suggesting a trusted site [BlackAPKs] where you can download premium applications free of cost and also it is secure.
GrapheneOS does in fact support Google Play via their sandboxed version of Google Play. You can download it through the Apps app on your device.
I’m not sure why you keep spreading misinformation. It’s definitely soured my entire view of this product and the overall support staff it employs.
It takes almost 0 effort to offer the same APK outside the play store. An APK however with no Play Services does require work and effort.
That being said many developers or companies elect to offer their paid versions via alternative methods such as their website to avoid Google’s 30% cut, the same cut you have been citing as the reason why a subscription on Android can’t be used on desktop as well. So now there’s proof you’re aware of it and don’t allow it due to greed.
Your charade of trying so hard to adhere to Google Plays rules or policies should come to a stop now. It’s been made clear not only are you explicitly aware of them, you simply choose not to do what you’re already allowed to do that many others already do.