Do I understand correctly, what you mean is that there is an Invidious instance to which two users are connected. User A sends request to Invidious to get a video, Invidious forwards it to user B, user B downloads the video and sends it back to user A?

Sounds a lot like Tor or maybe I am missing something?

Sounds cool asf, probably the way private messaging apps should be

Although, it is not really fitting my threat model, I would love to see how it develops

Lol

Smartest TikTok user

Stop switching to every new “cool” and “encrypted” service every time the previous one disappointed you a little bit. This is not helpful neither for your time, nor for privacy community overall. We should lean on most developed and best platforms we have right now (Proton, Signal etc.) and get everyone to switch. Unless we know we have market dominance, dispersing our efforts is futile.

And yep, answering your question, Tuta Mail is fine

deleted by creator

Graphene OS - best privacy and security, only for Google Pixel phones

Calyx OS - less secure but supports cheaper phones (Motorola) and eco-friendly phones (Fairphone)

Honorable mentions are LineageOS, /e/ OS, Replicant and iode OS, however their security is much worse than of Calyx/Graphene (no verified boot), so use at your own risk

Yes, they exist, but there is no reason to use them other than tinkering around. Also they have much worse security than Android or iOS. So if you need something private and open source there are a plenty of degoogled Android ROMs.

They are not called tankies because of rolling tanks though

The term “tankie” was originally used by dissident Marxist–Leninists to describe members of the Communist Party of Great Britain (CPGB) who followed the party line of the Communist Party of the Soviet Union (CPSU). Specifically, it was used to distinguish party members who spoke out in defence of the Soviet use of tanks to suppress the Hungarian Revolution of 1956 and the 1968 Prague Spring, or who more broadly adhered to pro-Soviet positions.[6][7]

From Wikipedia