KDEConnect - I use it on Windows and android phone. Very nice when you get security codes or links on phone, want to send files or when I want to control audio|video and I watch from the couch.
in general: Fdroid nearly always has a more feature rich and performant alternative
Guys like you see privacy as a monolith, that it never is. Unusable privacy is meanigless as email had shown. Privacy of communications does not mean privacy of communicators and usable authentication can be more important then anonymity.
And all this has to be realised on real-world servers, that are always in reach of real world goverment.