Best security: avoid it

+1 for Termix Next on my list is to test the integration with https://github.com/warp-tech/warpgate

Can uploads to Proton Drive be automated?

You/users have a choise. Use privacy invasive chat apps like WhatsApp, Telegram, etc for free or invest some time and/or money to self-host it or use their SaaS option. Either way, you’re far better than using WhatsApp. Signal is a very good option.

If you “don’t care about privacy because if have nothing to hide”, I recommend reading Means of Control by Byron Tau or just watch what ICE is doing with all the data Palantir is offering.

I’ve been using it for more than a year to communicate with my family and a very small group of friends. The video and audio call features are good and I’ve replaced phone calls and Signal/WhatsApp with it. Because it’s XMPP, there are many clients you can use, not just the Snikket app. Overall, I recommend it because of the End2End Encryption features and self-hostable (if that’s a term)