I see this discussion for Drupal 7 but am trying to do something similar in Drupal 9.
My view is called "content_display" and the display I am trying to affect is called ct_list (see screenshot). 
Currently an exposed form sorts by title(screenshot).
The All option is defined in the view and going to path/all shows all just like path/a shows articles starting with the letter a.
Seems like I need a hook form alter in a custom module but have not really done anything similar since D7.
Any help or guidance or resources is immensely appreciated!
