ConfigMapConfigMaps in kubernetesKubernetes are limited to 1Mib if. If your file could not be split or shrunk, iI feel like you should use a volume to store it using the storage class that your cloud vendor/subsystem offers you.
S3 is a good object storagestore, but you can't store configMapsConfigMaps in it. You can't use it either to store volumes. You could use EBS and EFS (since we are talking about AWS products) based on access pattern that you want to achieve for this filesystem.