I bought it, I played with this idea to push/pull with line tool in actual 3d geo extrude
Mainifold extrude is not great for this kind of stuff( i think they work on it to cut through but i’m not sur) however some addon succes to do it like Destructive Extrude.
is there a way to constrain straight line like C in blender knife tool ?
https://blenderartists.org/t/destructive-extrude-beta
no longer developed I’m afraid