Considering Action Surge and higher level Fighters combined with the high focus on verticality in BG3, I would probably still limit Shove to max 1 attempt / turn. At least make it Shove + 3 x Pushing Attacks for a 5th level Battlemaster to expend some resources. Action Surge is a pretty insane spike tbh.
Eh I don't agree but I'm not categorically opposed. If Shove is only 5 feet then it's much less powerful, and a fighter dedicating multiple attacks and possibly AS to
attemptshove a foe multiple times to off a cliff is fine to me. As long as instant-death pits and lava aren't too common of course. Theoretically an enemy should successfully avoid a shove ~10-50% of the time depending on the relevant skills scores, so even 4 shoves in a row will only on average yield 2-3 successful shoves = 10-15 feet.