New World players bring up something called a watermark and how it's terrible. Here is all the info you need to know to understand the term and the players' sentiments toward it.
Watermark in New World is called that way because it functions similar to a regular watermark but to understand it you will need to know the basics.
First, there is the Gear Score, which doesn't play much of a role before level 60. When you reach the max level, however, raising Gear Score from 500 to 600 is the remainder of your progression. This is where the watermark system kicks in.
Level 60 items in New World are based on different Gear Score brackets, based on the location you obtained them from. Once you obtain a sword with Gear Score of 520, for example, the system will "watermark" your account with this new data and you will be eligible to get drops with GS of 521 and slightly higher.
You will need to go through several brackets in order to reach 600 GS which eventually becomes tedius grind, which is one of the reasons New World players hate the watermark system.
Another reason to frown upon this type of gearing up is that your progress gets watermarked only when you get drops with high enough GS. Obtaining items with higher Gear Score through trading or buying from Faction Vendors does not progress your watermark.
Furthermore, each piece of gear has its own watermark. If you get 540 GS gloves, it doesn't mean all your armour reached that watermark - a chest piece might still drop with 520 GS. Throw in the randomness of drops, the number of different slots that need to be brought up, potential duplicates and you will get another huge reason to hate this system that is basically just a bunch of grind with disappointing results.