Not cosmic horror, or a film, but this video of the end of the universe feels like it fits the bill:
Fantastic. Also along the lines of the "vast and uncaring universe" mentioned by the OP is this recent Sci-fi film Aniara:
Both remind me of an author I was surprised had't been mentioned yet: William Hope Hodgson- in particular his book "The House on the Borderland". For me he's the most significant author of cosmic horror.
A few quick takes from Wikipedia:
American horror writer
H. P. Lovecraft listed
The House on the Borderland and other works by Hodgson among his greatest influences,
[1] and
Terry Pratchett has called the novel "the Big Bang in my private universe as a science fiction and fantasy reader and, later, writer".
The House on the Borderland (1908) is a novel of which
H. P. Lovecraft, in his long essay "
Supernatural Horror in Literature", wrote "but for a few touches of commonplace sentimentality [it] would be a classic of the
first water".
[6] The Night Land (1912) is a much longer novel, written in an archaic style and expressing a sombre vision of a sunless far-future world; Lovecraft described it as "one of the most potent pieces of macabre imagination ever written".
[6]
The House on the Borderland and The Night Land had a much greater impact on me than any other cosmic horror I've read, and yet... they're terrible. Lovecraft was being super,
super, generous with the qualification "a few touches of commonplace sentimentality". China Mieville refers to the Night Land as "incredible but difficult apocalyptic masterwork". We're not talking "Finnegans Wake" type difficulty:
And she asked me plainly whether I was not truly very strong; and when I laughed with young and natural pride, she caught my arm suddenly to discover for herself how strong I might be. And, surely, she loosed it even the more sudden, and with a little gasping of astonishment, because it was so great and hard. And afterward, she walked by me very silent, and seeming thoughtful; but she went never any great way off from me.
To be fair that's the worst paragraph from the worst chapter in his entire body of work, but it's best to be up front about it when recommending his work. Start with
The House on the Borderland if you're interested. It doesn't have the crazy anachronistic language. The table of contents for the book give a sense of what he's all about
I THE FINDING OF THE MANUSCRIPT
II THE PLAIN OF SILENCE
III THE HOUSE IN THE ARENA
IV THE EARTH
V THE THING IN THE PIT
VI THE SWINE-THINGS
VII THE ATTACK
VIII AFTER THE ATTACK
IX IN THE CELLARS
X THE TIME OF WAITING
XI THE SEARCHING OF THE GARDENS
XII THE SUBTERRANEAN PIT
XIII THE TRAP IN THE GREAT CELLAR
XIV THE SEA OF SLEEP
XV THE NOISE IN THE NIGHT
XVI THE AWAKENING
XVII THE SLOWING ROTATION
XVIII THE GREEN STAR
XIX THE END OF THE SOLAR SYSTEM
XX THE CELESTIAL GLOBES
XXI THE DARK SUN
XXII THE DARK NEBULA
XXIII PEPPER
XXIV THE FOOTSTEPS IN THE GARDEN
XXV THE THING FROM THE ARENA
XXVI THE LUMINOUS SPECK
XXVII CONCLUSION