Tablet note taking

Hello, I’m a Chem major in university and just finished first semester. I’ve used like 6 notebooks and it’s very time consuming to take notes, especially in organic.

I feel that a tablet for note taking would be very productive, but I don’t know which to buy.

I’m looking for something with good 1) battery life 2) display 3) comfortability with pen 4) pdf and general file format editors

Any recommendations are appreciated Thanks! :)