In order to reduce user-confusion during Sign in, please provide an organization-specific URL for the general Survey123 site, so that the Sign in link would direct users to their organization's custom Sign in experience.
For example, if a user went to https://umich.survey123.arcgis.com, they would see the same content as they would for https://survey123.arcgis.com. When they clicked on Sign in, however, they would be taken to the umich organization's sign in experience, rather than the generic arcgis sign in experience.
The umich organization would then be able to use their org-specific URL in preparing training materials, documentation, etc., Users in the umich org could also share links to surveys they've shared with other members of their org, so that they would get the umich login experience, and not be confused by the generic arcgis login experience.
See also Provide URLs for ArcGIS Online app web sites (Survey123, StoryMaps, etc.) to direct users to organiz....
