I personally quit 3H after the timeskip cause it was too stupid at that point for me to care. I do have the urge to give it another shake though.
I hope by good gameplay you don't mean all the busywork in the monastery. Hell 3H regular gameplay suffers too, I played the Claude route and had like three or four wyvern riders and a nuke mage plus Byleth being OP.
The game basically had no answer to that.
As for Echoes, it has by far the best presentation out of any Fire Emblem game, gorgeous art, great voice acting, great animations and I even like the stories and characters.
They really should've deviated from the Gaiden Map design, then I would've had an urge to replay it at least once. Even the post game content isn't any better.