Advice on introducing the party to Lolth?

As the title says, I'm looking for a few suggestions on an encounter to introduce the party to Lolth.

First, some context. This is not exactly the version of Lolth that you're thinking of. I've re-written a lot of the lore for my homebrew world, and in this one Lolth was formerly a trickster deity. In ancient times, Lolth and her followers defeated and imprisoned a powerful, evil being that threatened all of elvenkind, but out of desperation they did something terrible in order to accomplish that, and were banished to the underdark for it. Centuries of life in the underdark shaped their society into something harsh and cruel, because that's what it took to survive there.

The story so far: the party is investigating this event in ancient elven history, and have already managed to get on good terms with a secret order of Drow who guard this knowledge. The party has also knows of Lolth, not by name, but as the "trickster" she used to be. The next step is the party being told, "we don't share this knowledge with outsiders, but if you choose to face our trials, the goddess may find you worthy to join us, and then we'll tell you what you want to know."

And this is where I need a little advice: what should "the trials" be? I'm thinking of basically a short, linear dungeon where every individual "challenge" reveals a little bit more information, and the group just needs to survive long enough to get to the, "surprise, it was Lolth all along," reveal at the end. It could be anywhere from 3-10 challenges, because I can break up the info several different ways.

The challenges don't necessarily have to be combat encounters, it just has to be dangerous - or at least feel dangerous. Puzzles and traps are good, or some kind of "escape the room before the poison kills you" thing. I just don't want to just do, "spiders, spiders everywhere" because that would make it all too obvious (except right at the end, of course). However, I'm drawing a complete blank on what else to use.

So, any ideas are welcome!

I'd start by asking what qualities would make the Drow think the party are worthy. Given their society has become sharp and harsh, I would say that sharing their struggles and suffering would be a good start. What suffering did Lolth and her people shoulder to put this evil away?

Depending on how plot-critical it is that they succeed, I would consider something along the lines of a trial where the party has to endure, not to defeat. The unintuitive nature of this may require some means for them to work it out, so they don't just get confused.

The party is told "We have quietly endured suffering in the dark in taking the difficult road which led us here to our new dawn. If you can prove yourselves able to share in that, then you may be worthy."

The trial is a dark room containing a huge set of scales, on one side of which stands a large stone barrel, suspended by a taught rope which loops over a pulley on the ceiling, down to one on the floor, then across the room at about waist height to anchor on the far wall. The side of the scales on which it stands is up, and it looks like if the barrel were lowered, the scales would drop. On the other side, a stylised sunrise motif stands.

If the party cuts the rope, they will fail. They took the easy road.

If the party pulls the rope, the barrel will shift slightly - "It looks like if enough of you pulled at once, the barrel will lift". If all of them pull at once, the barrel will raise, and sand will begin to pour onto the scales from a hole in the bottom. At this point, large spiders (tarantula sized) will emerge from holes in the walls and approach the party. If the party attacks them, then they fail - they have not endured, they have fought.

If the party can stay calm an endure the spiders crawling over them whilst they hold the barrel up to let the sand fall out, the sun (other end of the scale) will rise, and they will have shared in enduring hardships in the dark to allow the sun to rise, and in their wisdom proven themselves worthy.