So I looked into this. Right now Zed is middle of the pack of the 4 cost 3 stars, and sitting with a 1.4 avg finish. For comparison, the BEST 3* 4 cost is Neeko with a 1.2 avg finish. Its not really unplayable.
One of the things that catch people off guard is that since so many 3* 4 costs deal SO MUCH damage, all of a sudden their BIS changes dramatically. Do you need IE if you spell already does 1200 damage? No, what you need is healing to go infinite. Its not intuitive, but it is what it is.
Sorry you had a rough game.