Rather old topic, but if you like to use the Apple Pencil and an iPad (pro) to build compositions it is worth mentioning Sidecar (https://support.apple.com/en-us/HT210380). It effectively extends your desktop to the iPad, so you can use it as a second screen. Pencil input doesn't work with all apps as of yet. My macbook is too old to be supported by this technology, but maybe someone can check it out?

There are more (paid) options like Duet Display, which seem to do the trick as well.