I've noticed is how damage is equal when you're not even hit with the blade
You're not the only one noticing this. The menavlion is routinely getting 1 hit kills even when swung from point blank range (and at the start or end of its swing, not sweet spot). Which is strange because my 1H sword or axe commonly glances for 5 or less damage but this super long goofy stick has the touch of death even at face-hugging distance.
People are even finding a way to implement the menavlion's op strength in competitive play like Skirmish Mode. In matches it's now common to see people go menavlion infantry and drop their menavlion for their cataphract teammates (who already go without shield), and as broken as the menavlion is on foot, it's utterly devastating on horseback. Even then, in team melee fights having a guy in the back with a menavlion taking pot shots is also just brutal, getting caught by any part of its swing usually spells instant death.
Shouldn't the menavlion just behave like a pike? With you know, only stabs? It already has incredible reach. The fact that it can be swung in and of itself is ridiculous and silly, and couple that with its lethal damage output and you have currently the most broken weapon in Bannerlord.
Also, I don't want to bring up the fun-realism debate, because that's a rabbit hole we've already been down, but in general the combat in M&B is "grounded" in realism, while realism is also not dogmatically adhered to (this is a good thing). The weapons in Warband that had high damage output had either considerable mass or high speed, or both (great hammer, morningstar, 1H battle axe, war axe, 2H mace/sword, bardiche, elite scimitar). There was a modicum of real-world science that could justify the amount of damage they did.
When you factor in things like force (mass x acceleration), leverage, circular motion, and weight distribution, the menavlion's current functionality makes no sense. It swings very slow, but there's not a lot of weight at the tip of it relative to the whole -it's just a really long wooden stick, and plus it's extreme length affects the leverage its user has on it. This is why when you first see someone swinging a menavlion, your mind -which probably has an innate understanding of physics even if you don't know the math behind it, most likely doesn't see it as that big of threat, then a second later you're scratching your head wondering why you died.