Is there a way to upload docker image to ECR in multiple steps?

ECR allows 250-500 concurrent parts to be uploaded for a layer in by default in ECR public or private repos. If you have enough bandwidth, you can request increase in this quota so that image could be uploaded within your time limit. You could also split your layer if they are big and not getting pushed within your time limit . See if any of the approaches in this answers work for that purpose.