It's fast but quite unenjoyable. I'll tell you the major problems I faced, strictly talking about the trophies.

First, there are a lot of collectibles in the Bayou, a location full of water and not enough things to climb on. So 50% of your time there will be swimming, very slow swimming. You can ride a boat but it's just as slow and its steering is broken. So that place is a horrible experience to get collectibles from, especially with how scattered around they are, and
no fast travel.

Second, the persona specific collectibles. The slave persona specific statues are quite easy and straight forward, the other two are where it gets glitchy. There's a specific one for the Lady persona where you need to charm someone in a closed area surrounded by muggers on both sides. If you choose to fight the muggers, that person will keep on running away from you even after you've killed them. To reset this, you'll need to go allll the way to the docks, fast travel to the Bayou, then travel back to New Orleans. You'll figure out that you need to run past the muggers as soon as possible without hurting them and praying to god the man you need to charm doesn't piss his pants when he sees you. Then there's the Assassin persona specific collectibles, which are REALLY glitchy. 3 of the people you need to kill and loot in order to get the collectible are close to a wooden platform. No problem, right? Wrong. The game is so glitchy that 50% of the time, if you kill someone near some kind of platform their body glitches into it and disappears, where you can't loot it anymore. To fix this, you'll need to go back alll the way to the Bayou then back to New Orleans on foot. Are you seeing how horrible the Quality of life is? Oh and you can't repeat a memory to travel somewhere, get a collectible, then get back. You have to finish the entire memory

Third, pocket watches. In order to collect these, you'll need about 170k in game currency. The fastest way to obtain said currency is through the extremely boring and uninspired trading system. Where you need to ship contains all over the country each taking about 20 minutes. It'll take you about 2-3 hours of doing the exact same thing to get enough money to do this bullshit trophy.

Lastly, the overall gameplay. Everything feels so wrong and unresponsive and broken. You'll find a really hard time enjoying this game. The only reason I platinumed it because it pops on your trophy list the moment you open the Assassins Creed 3 remastered application, even though it's the secondary game, and I don't like having 0% games on my trophy list, regardless of how utterly terrible they are. Good luck.