Hardening with Firejail, Landlock, and bubblewrap

Recently I've been looking into securing my laptop a bit. By default, every single program has access to everything: filesystem, network, other programs. First, I started looking into Firejail. It allows specifying paths the program can access, as well as the network and other special things. It's not bad and I used it for a while. What I don't like about Firejail is that it's setuid: it runs as…