It is possible to "disable" the Portal help to some degree, but not the server help. See this Idea: Disable web help - Esri Community
BTW: I highly recommend upgrading your 10.9.1 deployment to a supported release. Security-Patch Support ended four month ago: ArcGIS Enterprise Life Cycle | Esri Support.
It is possible to "disable" the Portal help to some degree, but not the server help. See this Idea: Disable web help - Esri Community
BTW: I highly recommend upgrading your 10.9.1 deployment to a supported release. Security-Patch Support ended four month ago: ArcGIS Enterprise Life Cycle | Esri Support.
It seems that hiding the Help page on Portal for ArcGIS 10.9.1 is not possible.
I'll consider alternatives that ArcGIS Hub. I'll push IT to update ArcGIS Enterprise. Thanks for the intel.