The Remnant games are a completionist's nightmare. Want a specific weapon or bit of kit for your build? You need to hope the right world shows up early (three of the worlds switch their order around each playthrough, so based on luck a specific world could be the first you go to after the tutorial, or it could only show up right before endgame), hope the right main quest for that world is picked (each world has two mutually exclusive storylines), hope the side quest and/or dungeon that drops that item is generated, hope the tile it spawns in is placed on the map (usually but not always guaranteed), hope you don't miss it entirely due to 90% of the world looking identical... and if it's dropped by an optional boss, you even have to hope that boss is picked from the pool of choices. It's insane how random it all is.
And it's not just gear. As you noted, the archetypes (your character classes) are also gated this way, plus have absolutely ridiculous unlock criteria to boot. Have fun finding the archetype that requires a leap of faith off a random border of a specific map into an opaque cloud of poison, then a second blind drop immediately after to grab another item before you choke to death! Don't worry if you didn't know about it, it's only the best archetype for fighting bosses as a solo player. Better hope that world showed up early in your playthrough and you are the type of player who's okay dying repeatedly while exploring - which, as this is a Souls-like, revives the dozens of enemies between the last checkpoint and the spot you died.
One of the archetypes was only found through data mining, the unlock criteria was so obscure. I shouldn't need out-of-game knowledge and to pass several dice rolls in a row just to have a chance at getting to content I enjoy.
It's telling that the class dedicated to exploration and level grinding is unlocked by beating the game. You're expected to play through the campaign several times to see everything, but since it's all random you're just as likely to roll stuff you've already done. Which the developers clearly realized since you can roll individual worlds as side adventures.
Though at least one thing that sets it apart from other Souls-likes is
that you don't drop or lose anything on death. However, they compensated for that by making currency drops a miniscule fraction of what they are in other games in the genre, necessitating even more grinding.
Edit: and I actually like Remnant 1 and 2. The gameplay and story are good, the worlds are gorgeous, and the voice acting is phenomenal, but it's all dragged down by the random generation mechanics. At least 2 is a solid upgrade on that front - the first game felt far more empty and lifeless.