If you own a device that is supported by a custom ROM such as Lineage OS then you can flash that and not worry about this change.
Otherwise, you can purchase a different device, preferably a Nexus/Pixel, or at least one that's unlocked. If that's impossible for you then, yes, you're stuck with AT&T's "best efforts."
Otherwise, you can purchase a different device, preferably a Nexus/Pixel, or at least one that's unlocked. If that's impossible for you then, yes, you're stuck with AT&T's "best efforts."