In case you missed it, there's a privacy-friendly alternative to Google Play.
It's called F-Droid and only includes free open apps that don't track you:
The installation process is slightly complicated, but once it's been installed it's extremely easy to use.
You can also follow F-Droid on here at:
Apparently Signal requires some sort of Google services:
That doesn't make Signal any less centralised.
I don't think it's useful to idolise famous individuals.
mastodon.at is a microblogging site that federates with most instances on the Fediverse.