If an app gets an update, where does the update binary (or apk) get pushed first: PlayStore or the 3rd party store?

So I am trying to get into these OSes like Graphene, Callyx, e OS..etc. If need be, I will try to de Google the phone too. Anyway, I understand that you can install apps using stores like Amazo, Fdroid, Acrescent, Aurora...etc, instead of relying on Google Play Store.

If an app I need relies on Play Store, then so be it; I think OS like Graphene allows you to run a profile with Google Play stuff?

Otherwise, I can just use apps from Fdroid, Aurora..etc. Say I have Firefox installed from Fdroid and it requires a serious security update, which store will get the update first: the Play Store or they come at the same time even to Fdroid?

Or I am a dev and I need to send an update for my app, where do I send it first?