Not all apps come with blazingly fast and convenient cloud sync features. Seems obviously basic, but my guess is such a feature is not in high demand for apps such as AdGuard. Apps that have rather larger spectrum of users, ones who simply download and use, and ones who meddle with scripts, tend to have divided functionality with some gaps in the middle. Long story short, if you want to synchronize your devices with one set of files via HTTP URL, (read: user rules in case of AdGuard) this is the way.