When something doesn't have time, gravity, and 3D ..what makes you think spacetime is involved? I'm talking about QM objects when they are unobserved and are considered waves (the unobservable). Have you considered QM might not exist within the fabric of spacetime until observation?
The Wave function wouldn't result in probabilities if it was possible to include spacetime. QM waves do not need anything from spacetime to continue existing.
Entanglement is obviously not a property of Spacetime. Spooky action at a distance can happen because QM doesn't have time like we experience and the particles are likely connected via a QM wave that could stretch to infinity if needed.
Abbe's diffraction limit is the cutoff we have been looking for. Anything smaller doesn't have to adhere to the laws of relativity. It's waves until it is observed. Observation seems to be a property of spacetime.
When a ginormous star collapses on a single point, the force is so extreme that it causes a QM bubble to scale in Spacetime that does not have to adhere to the rules of the QM/Spacetime divide. Like typical QM objects, it can't be observed but can pull in anything close to it. When two black holes merge, it's just the QM bubble getting more massive. It would then make sense for dark matter to also be overgrown QM objects.
Please tell me why you think spacetime is capable of performing quantum weirdness acts.