The highest tier in the game is legendary, but it has the same stats as ascended; only advantage is that they can be stat swapped. This also means you get the highest stats by achieving ascended gear. There are also these things called infusions that you can put in your gear for a minor stat boost.
For the most part, the stat progression curve in Gw2 is relatively gentle and there isn’t really that much advantage to be gained for max stat gear. There is progression in specific content though. You can also unlock elite specializations that alter the way your class plays, though some would argue you’re getting stronger as well. For the most part though, it is possible to outperform someone with better gear if you’re capable of playing better, so often times your success in combat has more to do with your ability to master to content as opposed to who has grinded more gear. But it certainly still matters.
Some infusions are specific to fractals, and give “agony” resist, something that is needed for higher level fractals, so there’s some degree of progression in the fractals without affecting the rest of the game.
There’s also the mastery system, which in the new Heart of Thorns maps, gives you additional abilities in those maps, so that may count as a form of progression as well. Central Tyria, aka all maps before the expansion, also has a set but those are largely just convenience abilities.
In World vs World, there are also masteries that you can get that give you additional abilities as well.
The most popular form of progression, and also the most expensive (thus the loot and economy centers around it) are revolved around the wardrobe. So people are usually grinding out for rare and cool looking skins. There is also a thing around luxuries such as convenience items that don’t really provide that much of an in-game advantage, but do save a bit of time. A lot of the drops are centered around acquiring crafting materials and components (many require you to spend time in a map to get them) to make all of this.
It does seem kind of unimpressive, but the advantage to it is that it’s rather open ended and you can set your own goals of wanting legendaries, rare exotic skins, min-maxed infusion ascended gear, etc.
As a new player, I recommend you stock heavily on crafting materials, as low-mid level mats are not easy for high level players to acquire and thus become rather expensive. Salvaging everything you find and selling the materials is an excellent way to build up a good stock of gold.
For once you have tasted flight you will walk the earth with your eyes turned skywards,
for there you have been and there you will long to return.
