Those look delicious. What are you scoring with? Looks like it may not be sharp enough or your stroke is too flat.
Scored with lame. My stroke was probably too flat, I think it came out better last time.
Pretzel buns are one of my favorite types. I usually make them rectangular if if using them for sandwiches though.
My recipe is also more like a Bavarian pretzel though, only flour, water, salt, and yeast or starter, not both. The flavor is also better with a lye bath instead of baking soda. It's a dead simple 50% hydration, so it easily scales.
Yours look very nice
We call those "Laugenbrötchen" (or "Laugenwecken", "Laugensemmel" – religious wars continue to be fought about this):
Never seen them made with sourdough, though. 🙃
52 Weeks of Baking
Welcome to 52 weeks of theme-based baking! A new challenge each week of the year. This is a great way for beginners to learn, and for experienced bakers to expand their skill set and explore their creativity.