When you quit a web browser on MacOS, windows and tabs just go away. Quitting a browser on the Mac can be disruptive if you quit your browser accidentally. All modern browsers added a feature that restores your previously-open windows. The only choices in Safaris General preferences tab for Safari opens with are All windows from last session or A new private window In Safari, you will in fact start fresh with a single empty window upon relaunching Safari.”]
Source: https://daringfireball.net/2020/01/quit_confirmation_for_safari_on_macos