DD2200 OS for reinstallation?

As a home lab enthusiast, about 6 months ago I acquired my first R710 and have been very happy.

This week, I expanded the system with a (2nd hand) DD2200 for a glorified NAS. This system came with all the HDDs removed for business security reasons. The previous owner was the original buyer and ran the DD OS for several years but now it has been removed with the HDDs.

How can I get a copy of the USB OS img required for reinstallation?

If not available, have I bought an oversized paperweight that needs hacking with proxmox or truenas instead?

Having trolled the dell site without and DD2200 OS images to be found, will they became public once EOL is reached at the end of 2023?

Any help appreciated :)