D&D 5E Need some help in my Descent into Avernus Game

[Hawk Diesel]

So I'm running a homebrew version of this game based in Eberron. So it's in truth more accurate to say it's Descent into Fernia. But anyways, the problem I'm having is the tone of the game. It has been very dark and gritty, which is obviously intentional. But it's gotten to the point where the players are feeling the despair and hopelessness, not just their players. I need a light side quest to break the tension and give the players a solid win. I have a few ideas, but I thought I'd put the question out there and see what the denizens here might suggest.

Also, to give a bit of context, they've been fighting their way into the depths of the Scab. They've nearly died a few times, and haven't been able to rest. They have a token that allows them to teleport to the Wander Emporium, which they used last session. So they are now in relative safety, as they have some good relationships with the people there. Part of this is going to be to give them the opportunity to shop to replenish supplies and get some rest.

 

[Quickleaf]

What about some "unfortunate souls" with comically bad deals made with devils? Like you can see the word play or twist coming from a mile away.

Spinning man with a crown: "I made a deal with the devil to help me turn my kingdom around, and proclaimed that I, as living embodiment of the land, would usher my people through this dark hour. But now I.... can't.... stop.... spinniiiing."