It must be possible to upload Spaces for WP Job Manager media to AWS S3 Storage (or another S3 provider) as well as to a CDN.
With Spaces for Job Manager, we have found that this does not currently work in conjunction with WP Offload Media:
If you have published a job via the respective Space, the company logo of the respective company is displayed as a broken link. Our debug log shows corresponding information about the possible cause.
pj