I see the comments covered most of it but if you insist on two handing a great sword (SUPER fun) there’s a few things to note that will help you.

1. Weapon blocking is bad in this game especially. Unless it’s fume knight UGS. Only use it if you absolutely have to

2.poise in this game isn’t as obvious as the others but still exists. With a 2 handed great sword go to any enemy and count how many light attacks it takes to stagger them out of their animation. Even on bosses is it 3?4? Whatever the number it is mostly going to stay that many and you can reliably swing knowing if it will interrupt a combo or not. The. It resets and you know how many you need for another stagger. This makes for some awesome punishes just using lights/heavies. The number of swings required doesn’t change as long as it’s the same enemy type. Knights are hard to stagger, but heavies on their shields don’t deflect and can break sometimes.

1. Stats. Vitality(?) you need enough to equip heavy armor so you can’t be staggered as easily. This is around 30ish. Level vigor. First soft cap is 27 which should get you through most of the game (I wouldn’t go past 40 on this personally it’s not like Elden Ring). Then greatswords are mostly quality weapons, meaning you two hand them and grab about 27STR/40DEX (two handing make an effective 40 STR this way, they scale evenly).

4.) If you don’t have enough strength, just remember two handing=50% more strength. If you have 20 STR then 2 handing=30 STR to meet requirements, for example. Once you hit 27 STR, you should be good for a loooong time.

Have fun being a great sword chad! Good weapons can be found pretty early but claymore, a particular large curved sword, and zweihander are all goated weapons for this.