Another vote here. Full screen would make the reading and writing experiences more immersive by far.

Came here to add this as a request – I’d love a way to add annotations “next to” a PDF page – that is, I have imported a PDF, and I am highlighting on it, but there isn’t enough space on the PDF for me to add notes there. What I would expect to be able to do is have the ability to write notes “next to” the PDF - conceptually similar to how Word shows comments off to the side of the main text of a document.

This definitely feels like one of those things that should be a basic benefit of digital notes - the software obviously knows what the date and time is. Coming back to a notebook and adding a note would be a great time to automatically add "october 1, 7:13 am" or whatever someone chooses as their preference.