Just get a Pixel and flash GrapheneOS.

You may want to look into CerberusApp - I know, it’s controversial and not FOSS, but it works great for me.

Really don’t get what all the fuss regarding Sync is about. There are plenty of alternatives out there, free or not. Maybe someone can explain what I’m missing?

Well said!

Visualising it, it’s nowhere near as far as it sounds.

A few years ago, I would’ve said Ruby. Nowadays, it has to be Python - it’s simple, readable, clean and more performant than ever. The fact that is widely adopted and used in a wide range of industries probably helps a lot.