Is this an underproofed loaf, and if so, why?

Hello all you knowledgeable bakers!

So, I'd really appreciate some input that may help explain the visuals of my latest bake (pictures below).

I don't particularly hate the result as it kind of ticks my boxes in terms of looks, texture, and taste. However, I'm a bit surprised at how it turned out and would of course always like to get a better sense of why stuff happens with the potential of more intentionally making it (or not making it) happen in the future.

In short, compared to recent breads, this one came out with a slightly denser crumb, and I don't know why.

I'm very much on the beginning part of the sourdough baking journey, and I generally vary a small part of the baking process every time I bake in order to learn (and perhaps even improve a bit) while still having some sense of what my changes mean.

This time I did a slightly prolonged bulk fermentation + cold proofing than usual, but attempted to keep other things the same, as I had gotten the feeling that I might be underproofing my doughs. However, the result I got after doing so looked even more underproofed than my previous breads--at least to my untrained eyes.

What particularly surprised me was the somewhat smaller hole structure in the crumb compared to my recent loafs. That and a more cracked crust (which may perhaps, however, be explained by a more shallow scoring than usual) along with a more caramelized, dark surface despite a slightly shorter baking time than usual.

Perhaps I was wrong about my underproofing hypothesis, or perhaps something else affected the result here. I'd love some input on this and perhaps other observations that could help me interpret the looks of the loaf and figure out how to go on experimenting in a meaningful direction.

Some more details on the bake:

400g wheat (11.5% protein), 50g whole grain "ølandshvede" (an old Scandinavian wheat variety), and 275g water (yea, it's a low hydration 65% bread) autolyzed for a couple of hours.

I then add 100g peaked 100% hydration starter and around 10g salt to the mix, let it rest for a bit, and then do 4 stretch and folds in the span of two hours (until I can do a decent windowpane test).

So, here's where I changed it up a little compared to previous bakes. I wanted to push the bulking further than usual and ended up letting the dough sit covered for around 3 hours on the counter on what was also a summer day with a room temperature of 25 degrees celsius (77 degrees fahrenheit), which is around 4 degrees more than my typical baking days, and which seemed to definitely get the dough to where it needed to be (again, judging with my untrained eyes).

Then preshaping, resting, final shaping, and finally in the banneton for an overnight proof in the fridge at around 3-4 degrees celsius. This is all pretty much as usual as well, though I also let the dough sit in the fridge for 4-5 hours more than with my usual bake--a total of 17 hours--after which poke test looked reasonable (not really being sure if it's super meaningful to use that test on cold dough, though).

Ending the process as I usually do with preheating oven + Dutch oven for 45 minutes, getting out the dough, score it, then bake it for 20 minutes with the lid on and 20+ minutes with the lid off until I'm satisfied with the color.

Alright, apologies for the novel here, but wanted to be as specific as I could. Feel free to comment on whatever--even if it's just a "good luck next time!" ;-)

Much love, Espen