It's not that hard really... application-level firewall, only allow the apps you actually use. Or you could block all access from your router except to a proxy, and then configure just the apps you use to use the proxy. Eliminates 99.9% of unwanted outbound traffic.
Many other OSes, distros and apps phone home/have telemetry too (yes even Linux ones), it's not like this is some egregious behavior nobody else does.