bubblewrap does this and has been used by flatpak for years. firejail has a lot more features though (which is questionable for a security-critical application,

bubblewrap does this and has been used by flatpak for years. firejail has a lot more features though (which is questionable for a security-critical application, sure), like setting up separate iptables rules, which you would have to do manually with bubblewrap.