The Site Tagline is indeed on the Dashboard Settings menu, but it is also found on:
Customizer -> General Options & Admin -> Site Identity -> Tagline
You can also set the Logo, Site Title, and Site Icon on that menu.
On most themes, the “Site Identity” menu is found at the top level of the Customizer Level, but it was relocated for Weaver, along with the “standard” top level options Homepage Settings, Background Image, and Additional CSS to appropriate locations in the Weaver Menu hierarchy.