We launched an on-premise ArcGIS Enterprise Site "Citymap" as a public geoportal for the citizens of the City of Luxembourg. Unfortunately, the listing of a Site in the search results of engines like Google is in the need of improvement.
I guess due to the dynamic generation of Enterprise Sites (everything that follows the "/portal/apps/sites/#/"), crawling becomes difficult for search engines.
Support for HTML metadata such as keywords as well as crawlable / searchable content is in high demand.
I noticed similar limited capabilities when trying to analyze Site traffic with an analytic tool like Piwik / Matomo.
For such applications, it is not even possible to recognize the name of a site.