Are the achievements new?
They’re different, well, some of them are.
Firstly, the general Crown Pavilion achievements (aka, everything except for the Gauntlet) and the Bazaar ones count for the meta, as in, they’re mixed together.
Secondly, in regards to the Bazaar specific ones, some of them are the same like opening zepherite baskets, aspect arena/ sprint achievements and finding the crystals, even though a lot of crystals are now in different places and they’ve introduced a new kind of master crystals that count for a different achievement. Apart from that, you have new achievements that are connected to the events they’ve introduced like the dolyak race and the crystal essence event.
But long post short: most of the content is indeed rehashed and redoable. It’s still very much worth revisiting the Bazaar though and Dolyak race is fun.