I agree with Axel, the toughest part was getting the display off. I left the watch on my 3D printer heat bed, set at 80℃, for about 15 minutes. After that the watch was so hot that I had to use a glove on my left hand to hold the watch down. Also, the curved blade is extremely important.

Apparently the AC cable is replaceable, yet not meant to be user-replaced: https://9to5mac.com/2018/02/10/remove-ho...

It seems that there are no true larger capacity batteries for this Macbook. Ones that claim higher capacity are usually of dubious quality.

Quick tip: If you keep the captive screw on the right side held up, it helps a lot. Also, taking it completely out when reinserting the PSU helps a lot too.