Sure, you can use something like bubblewrap, but it doesn’t make applications easy to sandbox. E.g. how do you sandbox an application and still make it possible

Sure, you can use something like bubblewrap, but it doesn’t make applications easy to sandbox. E.g. how do you sandbox an application and still make it possible to use Open/Save dialogs. You need to use something like portals like Flatlak does. But the Flatpak sandboxing model is clearly inspired by macOS and hated by a significant portion of the Linux community.