What's the difference between nxtheme and szs?

NXThemes works on every supported firmware and it’s legal to share so it’s allowed on websites like GBATemp or Reddit. SZS is firmware dependent (aka crashes on the wrong firmware) and NOT legal to share. You shouldn’t be posting szs links on other sites. To install NXThemes you need the NXThemes Installer homebrew (which can install szs files as well if you’d like) https://github.com/exelix11/SwitchThemeInjector/releases