IMO the Holy Greatsword is the best weapon.

[TooHigh2Die]

Not sure if it's the exact name but it's weapon you get for killing the fire shield guy. The normal weapon is really not that great but once you activate the ability and cause the handle to extend, it becomes an extremely powerful and far-reaching weapon. The heavy basic poke that reaches out 10 ft can easily cheese a lot of those pain in the ass mini bosses.

[Reralt of Givia]

You mean the Holy Sword of the Ark, right? I think it's a good Motivity weapon. It's extendable, has good stats, and the sword's skills are good as well. I'm currently trying out the Proof of Humanity sword. I think it might be good too.

[Krispy]

I used the holy greatsword in its normal mode for 90% of my playthrough and it is amazing. Super high damage, the Y attack comes out really fast and stuns, has hyper armor so you cant get knocked out of it usually, and looks pretty stylish on top of all that.