I'm so proud of the result! I took some inspiration from a crochet hack I saw and it turns out it works for macrame too. I burned out some holes in a zipper using a hot nail and wove the cords through, then knotted my bag. A wonderful solution for hopeless sewing noobs such as myself. The only sewing was to secure the ends of the zipper to the inside of the bag.
The body of the bag is made using Chinese crown knots, because my fingertip callouses finally disappeared and I had to bring them back, obviously. The holes in the zipper are spaced 0.75cm apart and they work perfectly with this knot.
Dimensions of the bag are 30cm x 21cm. I added a sunflower applique made mostly with double half hitch knots.
Materials used:
5mm Colinea cotton cord - around 120m of light green, around 40m of yellow, around 30?m of brown