Hello Tlor,
As far as I know, there are no major differences between the Boox Air 2 and the Boox Air 2 plus. The Boox Air 2 Plus has a better battery, which makes it slightly heavier but apart from that it seems to me that the rest is quite similar. I have the Note Air 2, I can write/draw with the stylus in the note taking app and also on PDF.
Here is the Boox (Onyx) website for reference:
https://shop.boox.com/collection... The site is in English but there is a comparison between the different models at the bottom of the page.
Greetings