Alright, I played a bit more and have more feedback:
Let's start with some standard 3D platformer stuff.
Adding drop shadow and coyote time would improve the platforming.
Some concerns regarding the fighting . When fighting those punching and sword-wielding mushrooms, it feels like they attack continuously, and the only time I can try to damage them is after a perfect parry. I would suggest to make them have at least a bit of a stop after attacking.
I would suggest adding a form of "aim assist." By this, I mean that if the player is almost rotated in the direction of the enemy, the player should be rotated directly toward the enemy. I have implemented this in my game, and I believe it was a valuable addition.
"example of adjusting players rotation towards enemy when attacking from my game"
It would be usefull to make it a bit more noticeable when the enemy is damaged, perhaps by having the enemy flash white or red when taking damage.
Also I would make it more noticable when enemy would parry your attack like a sound and some particles when enemy starts a perry.
"like here for instance you can clearly see when counter starts (gif from SSBU)"
I haven't finished it yet (at least not as of now). I've collected 3 keys and I couldn't platform to the location where I believe the 4th key was located.
If you are looking for a similar game to get some inspiration or check what quality of life features you can add to your game I would reccomend these two 3d action platformers with melee combat "Pseudoregalia" or "Blue Fire" ( but Blue fire I would only reccomend if you can get it on sale)