I plan to have an electrician do the 'official' installation. But I'm curious about this hole in the Starlink Pole Mount - the instructions refer to a "drain hole" and a "cable routing hole". Is this hole (yellow arrow) both of those things? Thanks for your help.

David, I am not an expert installer and the way I did was the best with the info I had at the time
You do not need the pipe adapter, if you are using the mount sold by Starlink, The pipe adapter is to use when the pole mount is a regular pipe you use instead.
The Standard kit cable worked very well to route the cable inside, The High performance kit, the cable is thicker so you have to run it outside or just enlarge the upper hole to be able to run it inside the pole like I did.
I attach the instructions that came with the Starlink Ground Pole Mount