Have been in that situation. If you leave, you're done. It's up to the other co-founders if they want to throw you a bone to keep a relationship in place. The leaver is dead to the board and the investors. It's your business now, move on.

is it tho? like i agree if i just took the equity. but if i own a ton of equity and the board wants to clean up the cap table, don't they still need to deal with me by offering me a fair number instead of "just moving own"?

Not sure they need to do anything. Maybe in the interest of smooth sailing, and closing things off, then the board might be motivated to reach a mutually acceptable conclusion. Whether this be a little buyout, an advisor tie-in, etc, completely depends. Situations like this is why founders create equity agreements.