Furthermore, you could test this a few ways. Hex someone's Dex and then try to shove them. See if they do it at disadvantage (I think you can find this in the combat log). Repeat with Grease (shouldn't but again, who knows). Also attempt choosing STR for the shove test since normally the person being shoved or grappled has a choice between Athletics (Str) and Acrobatics (Dex)... though if they're smart like a player they would pick the one without disadvantage so (shrug).
