I bought these hoping they are good enough for my medium nib... (Set of 3) A5 Dotted Notebook/Travel Journal - 5.5 x 8.25 Dot Grid Paper for Bullet Journaling, Total 120 Sheets/240 Pages, Black/White/Kraft Brown Cover https://www.amazon.com/dp/B072FDGMW1/ref=cm_sw_r_cp_tai_2uPBAbE39M1TM
I just like simple minimal notebooks that I don't feel bad writing and making crappy drawings and maps in:
Dot paper really helped me. If you're unsure about it there are pretty cheap mini dot grid notebooks on amazon that you can test out before committing to a more expensive bigger book. here's one and here's another
I've used these on Amazon before - my mom bought a set of three and gave me one, so I used it as my first bullet journal. they have a soft cover, but they shouldn't get too beat up since you aren't using it long-term!
As far as pretty goes, you could add a scrapbook paper cover. Like archeranchor said, they are fairly easy to make as well - just print dots or lines and you can use an awl and heavy thread to sew together if you are crafty at all!