Our MMORPG characters are usually extremely strong. However, they usually also have limited strength.
Probably that’s why you can’t carry 1000 swords in your inventory all the time.
There is no one static amount of items you can carry at one time in New World. But this doesn’t mean it’s unlimited. Of course, it is.
Everything depends on your maximal encumbrance (you can check it in your inventory at the right top) and on the item’s weight.
Some items weigh about 5 (there is no specific unit), while some others weigh about 0.5, so you can carry ten times more of them than the first ones.
You can check the item weight by hovering over it when it’s in your inventory.