With just the main Steam window open, I have 8 steamwebhelper processes listed in the task manager.

Some more details (pieced together from the task manager and the chrome://system page):

• 1 main process (simply called Steam or Browser)
  
• 2 render processes:
  
  • one for the main window (and for sub-windows such as the Friends List)
    
  • one for the displayed web page (e.g. a store page, the Library itself, etc)
• 3 utility processes (Storage, Network, Audio)
  
• 1 GPU process
  
• 1 crashpad process (for saving crash logs)

This makes 8 steamwebhelper processes in total.

Each new tab (in a new window / on the overlay) will create an additional render process).
How many tabs do you normally open at the same time?

Two. Closing them took away some of the wbhelpers. Disabling overlay even more. Thank you