Simple and direct, discs for disc-binding notebooks.
Buy some sheets, appropriate for that kind of biding of course, and assembly your notebook.

The 20mm version supports up to 50 sheets.
The 50mm version up to 100 sheets.

Unfortunately, it needs support to print, I used tree support, it was not that hard to remove after.

Creality

Ender-3 v2

No

Yes

0.2

0.2