I had not thought of windowpaning the dough. Is that how you tell whether the gluten is adequately developed?
Yes. Dough can be a long way from optimal gluten development even once it achieves some coherence in the bowl.
As to degassing, I thought I was supposed to keep as many much air in as possible, just work out the biggest air bubbles.
I didn’t look at the recipe and it might well say that; many of them do. Still, that’s usually something that’s applied to an artisan type loaf, not something you bake in a loaf pan where you’re not really after large holes. One of the reasons we “punch down” the dough is to redistribute the yeast food so that they can keep producing CO2.
Edit: Took a look at the recipe and she mentions “deflating and folding the dough”, so there is some amount of degassing expected. Still, she cautions the baker to “maintain as many of the air bubbles as possible.” I think what she means here is don’t overdo it. Even for the artisan types loaves, when you watch videos of the professionals, they still take a firm hand to the dough to eliminate large air bubbles.
Regardless, the first thing I’d check is your gluten development. Rose calls for as much as 10 minutes on #4 in a KitchenAid, which is a pretty long time. (KA says don’t go over 2, BTW) If the dough is sticking to the bowl, then even that might not be enough. That’s why a gluten window would be a good check on this progress.