Any tips for increasing rise when baking a boule (round loaf) in a dutch oven?

Current recipe is mix, fold a couple times, let rise, knock back & shape, let proof, then right into the hot dutch oven.

I notice the dough ball inevitably loses a little gas when I remove it from the bowl before placing it in the hot dutch oven. Tips to minimize this or increase oven spring would be great.

It's 83% unbleached all-purpose flour, 15% pre-hydrated oat bran, 2% vital wheat gluten. Hydration is 80%. I don't know if that's a little or a lot of gluten. Rise is not bad at all but I'd prefer it just a little more airy!

I am not a bread expert at all, but I would suggest bread flour instead of all-purpose. I think that extra protein will help gluten development.

I have also thrown some ice cubes in the dutch oven to steam the bread and help the crust to remain pliable so it can rise more. But I also cracked a clay dutch oven doing this, so be careful.

This is good advice. Bread flour (not breadmachine flour) has better proteins for building good bread structure. I found loaves were much higher and less stodgy with proper bread flour

Have you tried with the lid on the pan for the first 15 minutes?

I do on for the first 30, off for the last 20. Making this recipe for the third time tonight, I'm fiddling with variables and seeing what happens!