Grids with opposite attributes often suffer from interchangeability.
In this case it could be underachiever/overachiever, underflow/overflow, underappreciated/overappreciated, which makes the connections not unique.

thanks for the puzzle!
what the previous writer said is helpful-
I love red herrings, but when there are too many, it becomes frustrating.
More than one of these could fall in both categories, overweight, underweight, etc.
Looks like this is your first puzzle, good job- there’s a bunch of clever things in here.

Grids with opposite attributes often benefit from interchangeability.
In this case it could be underachiever/overachiever, underflow/overflow, underappreciated/overappreciated, which makes the connections not unique. Pretty cool! Just like the show