I guess some clarification is needed. Signal uses Google's notification services. When installing Signal on a device without Google Services, it says that the notifications might be unreliable because of the missing library.
But Telegram notifications work great, without relying on Google's servers, so I can happily use it without being monitored by Google...
Why Signal, a privacy-focused messenger, insists on using google servers?
From February 2014[32] to February 2017,[65] Signal's official Android client required the proprietary Google Play Services because the app was dependent on Google's GCM push messaging framework.[66][65] In March 2015, Open Whisper Systems moved to a model of handling Signal's message delivery themselves and only using GCM for a wakeup event.[67] In February 2017, Open Whisper Systems implemented WebSocket support into the client, making it possible for it to be used without Google Play Services.[65]
But Telegram notifications work great, without relying on Google's servers, so I can happily use it without being monitored by Google...
Why Signal, a privacy-focused messenger, insists on using google servers?