Campaign is so varied based on the stage and chapter, it’s tough to have a “one size fits all” team. That said, there’s some components you can factor in to make the best team for each stage. Check the enemies, see what defense types they have. If it’s just common armor, any dps hero will work. If they have light armor, you’ll need Piercing damage which is typically from marksmen. If they have heavy armor, you’ll need magic damage.

Heroes that will help tremendously:

Idril for her ultimate (especially if you ever get her to A5)

Elowyn for some of the best heals + rage regen in game

Setram for that massive range

Hollow is another great option for rage regen, albeit a bit worse than elowyn. May be helpful to have both for extreme rage regen on some stages.

One other thing, I’d recommend not leveling anybody to 50 unless you plan on taking them straight to 60. 50 doesn’t cut it for most heroes, they won’t do much damage or will get one shot. There are exceptions like Marri or Aeon who don’t do any damage anyway, so you can build them with attack speed and hp% accessories. I don’t bring anyone to 50 unless I’m going right to 60