Edit: thanks for all the advice! I worked these half as much, and made sure to let them cool. Great, round results!!
To start, I'm using this recipe: https://www.epicurious.com/recipes/food/views/bagels-366757
My first try I used AP flour and honey (both in the dough and the poaching liquid). Resulted in bready bagels that didn't have any of that chew on the inside, or the outside.
Second, I switched to diastatic malt powder on the dough, and bread flour instead of AP. I also increased the cooking time to 12 minutes per rotation (because after 8 and 8 they weren't golden brown).
The second resulted in almost crispy outsides (probably a little long in the oven, and the use of a dark pan, causing this), but gummy insides, and flat bagels. There was almost no rise at all, and cutting them resulted in most of the insides ending up on the knife.
Is this a proofing issue? Are the bagels not being allowed to come up to temp long enough outside of the fridge (they are passing the float test after 60 minutes)? Am I over-working the bagels (I'm doing 3 minutes per round, with a 5 minute break in the middle, on a pro series kitchenaid stand mixer with the dough hook).
Which step results in an underbaked-tasting gummy inside? What do I need to do to get a more tender (albeit chewy) interior and a good rise?
Attaching three photos. You can see the lack of rise in two of them (flat bagels, and holes that don't seem like they closed up very much). You can also see the knife in the background, with the gummy insides all over it. Last one is the dark bottom (again, I think this is pan related).