This read is interesting and makes me wonder how can we fight back. I don't undrstand much of this but what i have figured out is that its based on tracking phone IMEI. Presumably OSs like GrapheneOS cannot spoof the IMEI because its used to route traffic to your phone isn't it? I know it can use a different MAC for different eifi connections, trace reducing the footprints you leave behind but i guess it can't do this for IMEI?