S3 (anything Amazon) is most costly approach you can take.

Best you book a call with me or someone who works on this type of project daily.

For EBS/NFS, all slow/glitchy tech. You'll only use this type tech if you love daily aggravation + have infinite free time to debug problems.

Better solution, use OVH data storage servers, then run Linux on these along with whatever distributive/network filesystem is required for your workflows.

Since you don't mention type of workflow, no guess what a better answer than NFS might be.