You can compile your compiler from source.
Edit: Here’s how: https://www.linuxfromscratch.org/
Edit 2: I know you can hear the rabbit hole calling to you. Join us. Follow the rabbit trail.
But seriously, it’s cool, you’re curious about it, and the pay from the jobs it leads to tends to be pretty great.
It depends how far down the rabbit hole you’re willing to go.
Today you can make sure the source code is truly what you intend, by running Linux on PC and GrapheneOS on Android. You might not have the ability to audit those, but others (like me) do, and are doing so.
Whether you believe us or not is more philosophy - but join us in the rabbit hole and see what you find. You’ll find detailed public technical discussions of security and privacy. You can find some of that for closed software and hardware too, but we can never do as good of a job in that discussion without the source code.
If you want open auditable hardware, you can stick to Raspberry Pi.
There’s an open hardware project for phone too, but it’s more of a proof-of-concept, today, as far as I understand.
If you want the TL;DR version of where I landed - I posted this from a Pixel running GrapheneOS.
If you’re interested in that level of control, it’s time to look hard at GrapheneOS. “Internet” is a permission you can grant or deny for each app, under GrapheneOS.
But I’m not aware of a way to selectively direct phone traffic through Proton VPN, at the phone. Even on GrapheneOS.Enough skill with an expensive router could do it, but only on your home network, or only while routing all of your phone traffic back to your home network via yet another VPN.Edit: TIL, Proton VPN supports split tunneling. Sweet! Look under Settings - Advanced - Split Tunneling - then pick your apps to include/exclude.
Edit 2: TIL DivestOS also supports “Internet” as a per app Permission. Very cool.