I also prefer to invoke the delete and dissolve commands separately without calling the menu, depending on the type of selection. My keymap: X - delete, Ctrl+X - dissolve, Ctrl+Shift+X - Delete Menu. For me, this is a much faster way to work, as you do not have to stop and peer at the menu items. Fortunately, Blender has rather flexible settings and a large number of add-ons that could change some aspects to your preferences. I advise you to take a look at these two add-ons: