Used this in the past, so I can confidently say I didn't miss anything stupid in trying to open it now. Attached game, activated mono features, opened the cheat table, and then opened the side menu. I remember it working before, and sometimes you'd even have to go switch from Main Sim to either the dino or space one, or vice versa, but nothing worked for getting the menu to open. They've been doing some pretty significant overhauls of the in game menus lately, so that's probably why.
Hopefully this gets fixed! They added options that costs you hundreds and hundreds of Darwinium cubes, so, combined with how many cubes I've used in the past, you'd easily have to buy the $70 worth of cubes to get most things in the game. Even then, I think you could burn through them quickly. Definitely need this table to work now more than ever!