Dave doesn't want to be beholding to Microsoft or Apple for his operating system. He'd like to use Linux. Leo says that currently, a Chromebook is ideal for those who aren't their own support. But if you like Linux, then Leo likes PopOS by System76. What about Ubuntu? Leo isn't really a fan of Ubuntu any longer because of changes made by the developers. But it's base Debian flavor is pretty good. If you like the latest version of anything, then the Rolling Releases of Linux is pretty exciting as you get the latest version automatically installed. Arch Linux has one of the best communities for support. Manjaro is one such release, but it also waits a week just in case a bug pops up.
Additionally, there's a flavor of Linux for just about any computer, no matter how old. And then you can use free open-source software for just about anything. Is it secure? Leo believes that Linux is actually more secure than any other OS. One, because it has such a small footprint. Not as many users as Windows or Mac. But it's also got an army of enthusiasts that work on it to keep it secure.