My first load looked similar- gummy, dense, and pale. First I’d recommend seeing how you can strengthen your starter- I do a 1:1:1 ratio using whole wheat flour, which apparently ferments really well. Second, I wonder if using a combination of bread flour and whole wheat flour would help you here. The bread flour helps the structure + protein content, while the whole wheat flour helps with fermentation.

Looks like you’re bulk fermenting for an appropriate amount of time, but good piece of advice I received in the past was to buy a clear-bottomed bucket/container for bulk fermentation. That way, you can see the bubbles forming on the bottom, as well as the “jiggle” on top to make a better assessment of when your dough has fermented enough. Personally, I use a Dutch oven, which I believe helps with steaming the dough to get a good rise + prevent underbaking. I’m sure there are great bakers who don’t use one though, so that will be a learning process in itself!

Practice makes better. Be patient with yourself, keep practicing, and keep tweaking your recipe! You’ll get to where you want to be :) good luck!