Have you tried using Focus mode? This changes the UI to allow you to focus on either data or commands at one time and you can really view a lot of more data at once more easily.
To try go to View > Focus Mode.
Also if you want to hide and unhide many columns at once, select the columns (using the data table or the column list) then click the gear menu on the top left corner of the data table. Here you will find an option to ‘Hide all selected columns’. Otherwise you have to check them individually or use the group as suggested.