I'm considering restarting my phone, but I've been a purchased app for a year now. If I reboot on my Huawei, do I have to buy the app again?
Usually, your apps are connected to your Google Account. If you, for example, Look at your app list in the Playstore, there are all the apps that you once had, even those now uninstalled.
Thus, you no longer have to buy a purchased app after reset or device change, but only re-download and install.