

I’d go with the Debian package. That’s tied into the system. You get nice updates, there’s more eyes on what the upstream developers do, sometimes the Debian maintainers disable things like tracking, fix vulnerabilities in libraries. It’s smaller, less permission issues… It’s just safer and more convenient…
I’ll go for Flatpak once there’s some benefit. For example the sandboxing which is great to have for proprietary software. Or if the package isn’t available in the Debian repositories, and the alternative would be some third-party repo or deb file downloaded from a random website. And in rare cases when I need a specific version and the Debian maintainers are stuck with an old release.




Even if you control your router/modem, they still control the other end, it connects to. And some more infrastructure along the path. So i think it depends a bit where you’re going with this. If you’re worried about them doing packet inspection, or logging IP numbers you connect to, I don’t think there’s a big difference. They could do it anywhere. And they’ll likely do it in some datacenter.
A router interfaces with your local network, though. So in theory a router can be used to connect to your internal devices and computers and maybe you have an open network share without password protection or something like that. But we’re talking violating your constitutional rights here. It’s highly illegal in most jurisdictions to enter your home and go through your stuff.
I’ll buy my own router because I can then configure it to my liking. And my ISP charges way too much for renting one. And what I also do is not use my ISP’s DNS service. That’d just send every domain name I open to their logfiles. Instead I use one from OpenNIC