Ok I have done 31 echoes in the Fall of the Outcast area and I have yet to see a quest echo or the boss.
I seem to not understand how this works and seem to be just going around in circles. The last patch monoliths were straight forward and I usually could get the boss in 13 echoes or so.
Don’t feel that way. You are not the first, probably not the last not to see it. Its not “completely” 100% fool proof clear if you are not new or did not see the UI change with progress.