Well, it's OK to die in content, like I've died a lot in both old and new content, just that I end up looking up the YT guide later for the raid series or AR. No one really cares for normal dungeons or raids if you die a lot too.
The thing with DD or Eureka have special rules for them, they're not meant to solo'd unless for the titles, and you don't have to side content if it stresses you out too. I've never unlocked BLU since it didn't appeal to me back then, and now.
Also for solo duties they have a Very Easy setting and it works well.