Yeah I see what you mean.
What is bizarre about dmt, or at least in my experience of it, is this unshakable sense of infinity. I could have a feeling of no progression but still not feel that it's eternal, see. But with this experience there was this sense of infinity. And I wonder how that could be explained. What does dmt do to the brain, that its sense of finitude is blocked? or to put it differently, that the notion of death as being some sort of finality ceases to exist for the mind ?
Does this give us some deeper insight, when we experience this? Or is it rather the case that, our brain is at that moment incapable of accepting the idea of finality?

This exactly was the common theme for my dmt trips, the sense that it's all infinite and eternal, and that is terrifying. To feel that there is no liberation, not even in death. Or at least there is no easy way for liberation and the only way is through. Even rationally no one can prove that things will end at death and i think it's not wise to assume so and live based on that.
I think the rational brain is what imposes the sense of finitude to protect itself, simply because infinity is incomprehensible, even in the most rigorous mathematical terms. With dmt that sense is lifted.

Or perhaps, we "unlearn" the idea of death in the dmt experience , which is, after all, an idea we have acquired through learning* and which is not given to us from the beginning.

*(or rather we learn to assimilate the idea of death to our experience of going to sleep - of losing consciousness)

So, our idea of what death is like is false to begin with. It's based just on a comparison. On psychedelics, our "learning" in terms of metaphors and images becomes shaken, jumbled. I had mushroom trips during which images from my life would begin to appear as completely alien things (for example the image of a childhood friend came to my mind, but it felt like a bizarre alien thing that had nothing to do with me). I would recognize them as parts of my life, but i would feel completely dissociated from them, as if they didn't belong to me. Likewise, the lazy association of death with sleep/end of consciousness is something inaccessible to us during the psychedelic experience (familiar associations are dissolved... this is obviously one of the effects of the hallucinogen on the mind).
The psychedelic experience totally dissociates memories and acquired concepts from our familiar way of organizing them (this organisation is fundamentally fictitious but it is convenient), liberating them again, as it were (liberation not being a relief per se : madness is "liberation" as well). And then you can play with these things in a new way.
There was a Dutch writer, Rudy Kousbroek, who once wrote about lsd trip as a regression to preverbal reality. I always thought that an interesting thought.