Impossible smash burgers keep failing, how do you all do them?

Impossible smash burgers keep coming out too soft and falling apart, can't get a crust to save my life.

Is there anything, like breadcrumbs I can add to gain some kind of firmness? How can I get a crust without burning it?

Usual method is cast iron skillet, medium heat, ball up burger, smash, just using the natural oils in the impossible meat, season, flip, it is at this point the patty starts to fall apart, and then will proceed to burn if left for too long. The burning happens and no crust it just goes from 0-100 in theblink of an eye.

Am I doing the heat too high? Should I add another oil or fat like butter? Should I bulk the meat up with panko and/or onion?