IPad – macOS Notes app: zooming in on sketches made w/ iPad Pro

Here is the most convenient solution (Taken from http://www.quora.com/How-can-I-get-my-retina-Mac-to-not-take-screenshots-that-are-too-big and modified a bit)

Use OsX embedded Automator to downsize screenshots automatically after they taken.

1. Open /Applications/Automator
2. Create a "Folder Action"
3. At the top of the window, where it says "Folder Action receives file and folders added to", select "Desktop"
4. From the panel on the left, select "Files & Folders" and drag the item "Filter Finder Items" to the right panel.
5. Add the following conditions to the Filter Finder Items action: Name begins with "Screen Shot"; Kind is image.
6. (Optional step: if you want to keep copy of originals) - From the Actions list on the left, find "Copy Finder Items" and drag it to the panel on the right. Set the destination folder for the image copy (for example: "To: Pictures")
7. In the Actions library on the left, click on "Photos" and drag the "Scale Images" action to the right panel.
8. In the Scale Images action, select "By Percentage" from the drop-down and set the value to 50.
9. Select File > Save and give the Folder Action a snappy name like "Smaller Screenshot Copy"

Here is saved workflow file

The Notes application for macOS has been very unreliable throughout MANY macOS's so including Mojave! Even in the time it was still written as Mac OS X. So even if you cure your Mac, which you could do and I explained in https://discussions.apple.com/thread/251096810 it will most likely be temporary and at some point in time you will notice that the continuous spinning wheel in Notes will get back to nag you. And the non-syncing will be back again.

A better way is to start using Notes through the web interface, on www.icloud.com directly, and bookmark Notes for direct access. Its interface is smooth and complete and will allow flawless syncing with all your other devices like you iPhone and iPad where you leave Notes on.

Notes on iOS and nowadays also iPadOS however is pretty stable. So if you you these in combination with the Notes web application through the icloud.com website your are fine.