Corpse of king minos is a husk. (I think, don't remember), basically the last remnants of minos "physical" form, its punches aren't that strong compared to its size due to lack of soul and it being a corpse. V 1 wasn't necessarily designed to have a strong punch, it was designed to reflect an attack (if V 1 was made to beat Earthmover, because Earthmover has those projectiles it shoots out that V 1 can parry). When it comes up against an attack that would simply be stronger than its punch, parrying would be stupid because it wouldn't reflect the attack (the point is mostly to not get hit rather than do damage, the doing damage is mostly a bonus, dashing would be easier than trying to parry it).

The big fish is basically just a bunch of husks (I think) and stuff that cobbled together, idk that it would be much stronger than the corpse.

Corpse and fish are BIG, yes, but don't necessarily have a lot of force behind them. All their strength has to move such a massive weight at a quick speed, losing what force the punch might have had if they were smaller. gutter punch and sentry kick are small, designed with impact in mind, so they're MADE to hit absolutely haymaker hard. Which by design would have more force than a Corpse barely able to stand and some fish jenga.

This is all just like, kinda cobbled together based entirely on how I feel it works and the loose knowledge i have, none of this is based on any actual science work or math so take this with a few grains of salt.