I loved the concept and a lot of the imagery but yeah the ending skewed towards funny for me rather than scary. in the same vein, i loved annihilation for the same reasons but that ending was funnier than it was disturbing.
Annihilation didn’t do that to me, but I can definitely see how it might if your head-space slips outside just the right range near the end. A lot of that could certainly read as funny, in that case.