You can do this with chains of vulnerabilities, including but not limited to insecure redirects, CSP bypasses, insecure cookies. Another useful technique is session fixation - you give your victims sessions you've started and often their SSO experience will connect _their_ credentials to _your_ session.

Also to distinguish between #3 and, XSS in #2 was intended to mean "persistent stored XSS" as opposed to "reflected XSS". In the case of reflected XSS, this can be chained with CSP bypasses and insecure cookies to grab out e.g. bearer tokens.

My overall point is that heap fung shui 0day not required for 1-click ownage. In practice, I've not had to burn browser 0day to compromise organizations or their customers.