Frosthaven: some scenarios have been feeling just miserable to play. Any tips?

Just for context, me and my group finished Gloomhaven, FC and JOTL, so we're not new to the gameplay style.

In our group there's a Boneshaper (me), a Banner Spear (in some days) and the Trap class. I really do love playing my class, invoking an army of skeletons and I'm sad that I'll retire soon. But ever since my friend retired his Blinkblade for the Trap class, he just seems kinda miserable playing it, because out of 4 scenarios that he played, he felt useless in 3 of them. And yeah, when we have a 2 player party with just Boneshaper and Trap class, it has been reaaally hard.

After playing 3 consecutive scenarios in which the final goal just feels like bs, we've been feeling frustrated with the way Frosthaven scenarios are designed. And I don't know if we're just playing it wrong (which it doesn't seem like the case), if our party composition is just really bad or the scenarios were badly designed.

My main problem is when we've been playing for like 2 hour, session has been really fun and everything feels great. But then we kick open the last door and discover that our new goal is impossible because our classes can't do what is asked of us or we didn't know we were supposed to have brought a specific card.

This issue started with scenario 14 (this one was hard from the start), scenario 22 (we lost at the end) and last night we played scenario 9 (we cheated so we could win because we felt like we had suffered a lot and deserved it).

Scenario 9 spoiler: I think that one was the worst of them, because none of my summons focused the wall and just kept attacking the Oozes and I had already lost my ranged attack. The trap class also lost all of it's ranged ones, so we were faced with a indestructible wall of Oozes blocking our way.

At least in Gloomhaven, we knew from the start if we had to prepare for some special rule.

For an immediate solution, my group was thinking of putting a pause on either the boneshaper or Trap and start another class, just so that we can finish the scenarios until one of them retires.

Sorry for the rant. Still love this game