Try vastly differing movesets and playstyles to cover all your bases. I suggest a spear (partizan is one of the most varied, normal halberd has a similar playstyle too), Glaive (normal one), an ultra greatsword of choice (I find Greatsword and Cathedral Knight Greatsword to be reliable), a scimitar, a handaxe (it has a hybrid moveset between axe and a dagger), a dual weapon (sellsword twinblades for example) and a greatsword of choice (claymore or broadsword will do).
Then, once you find your most fun base moveset, you can find the best weapon within that respective class. For curved swords, pontiff knight curved sword tends to work best in majority of situations, while for greatswords Claymore and Onyx Blade are the most reliable.
The way you play will change drastically between weapon classes. With a 2h greatsword and a small amount of poise (~10) you can trade (multiple hits) with any light 2h attacks from daggers, straight swords, spears, pikes, mall axes, curved swords, scythes; with moderate poise (~32), with glaives as well; with high poise (~48) you can trade with small hammers, and if you get to 51+, you can trade with other greatswords. But if you chose to use a glaive or a halberd, you'll need 58 poise to trade just a single hit against a greatsword, so you'll have to rely on spacing much more than trades.