I’m not Melissa, but … I followed your bake and have made a similar Broa …
Melissa notes that the dough should “ferment until it’s aerated and domed (~6.5 hours in a 70F room)”. Those are the characteristics you are looking for to judge complete fermentation for this dough.
And the recipe photos show a before and at complete fermentation for her dough. The complete photo shows the aeration and dome that you are going for.
The tilde (~) means “in the range of” i.e. it is not an exact number.
Recipes for bread and particularly sourdough are more guideline than exact. As bakers, we all have to observe and make note of what things do, feel and look like, in our kitchen with our flours, liquids, temps, humidity and general stuff in the air that contributes to the fermentation process. It can be wildly variable for each of us … and even for each time we make a recipe.
And sometimes you are going to judge incorrectly. We all do . My own routine, particularly with a new dough (recipe), is to look at progress photos carefully and go for the look and any feel described by the recipe author.