I use the X1 Carbon and I am pretty happy with it. Compared to older models the keyboard and mouse (red dot in keyboard) are not as good as they used to be and the case does not shut in a way that the lid fits 100%. But other than that the laptop is a beast and I am happy that Lenovo gave up on stupid keyboards. The above made me consider to install Linux on a MacBook. Maybe that is something for you. It will not fix the keyboard issue but maybe the crashing when you connect external screens. Hope you find a satisfying solution!