Lee die disassembly problem

[charlie b]

Might be the worse choice in a wrench in this situation. (And many other). Open end wrench use is when you can’t get a a six flat box end or a socket on it.
I’m not familiar with the die in your situation but I sure am familiar with tools.
If it’s what I think a six flat box wrench and speed. Same if a six flat socket will fit. Violent fast yank.

The top of the Lee die only has two flats, so a box end or socket won't fit. A fall back is vise grips

The thing to keep in mind is that basically Lee dies are kinda disposable. If the die gets mangled it just means waiting a few days for one to be delivered by mail. Not like it is a Wilson or Redding competition die.