It's the opposite of what you say. Slim to none of the alternative cloud providers re-rent their GPUs.
Coreweave, Fluidstack, Lambda Labs, Paperspace, Cudo Compute, Hydra, Datacrunch.io, Vultr, Crusoe Cloud, SF Compute.
As far as I can tell none of these providers give you a GPU originating in Azure, AWS, or GCP.