Timeline with Muted Audio Mixer does plays Audio briefly when loading FROM/TO another scene - Unity Forum
Unity - Manual: Specifics on the Audio Mixer window
Unity3d: From an AudioMixer to a UI-Slider - Ko-fi ❤️ Where creators get support from fans through donations, memberships, shop sales and more! The original 'Buy Me a Coffee' Page.
Audio tutorial for Unity: the Audio Mixer | Kodeco