> Can I install those third party app stores on any Android phone?
Galaxy Store no (by Samsung's choice), F-Droid yes, Amazon Appstore I'm unsure. But for the overwhelming majority of third-party stores, yeah, you can install them on any Android device in a matter of seconds.
F-Droid is not allowed to compete on feature parity with the Play Store. You can't install apps in the background, do batch installations, or automatically update apps.
Galaxy Store no (by Samsung's choice), F-Droid yes, Amazon Appstore I'm unsure. But for the overwhelming majority of third-party stores, yeah, you can install them on any Android device in a matter of seconds.