Sounds like maybe you ran it as a container and didn’t mount the document archive externally then updated the container. That would have likely blown away the actual ingested documents but left the Metadata (including the OCR data) where it was, assuming the database was either its own container or mounted externally

Creating an AD domain carries a substantial amount of extra overhead that they might not want to deal with. The basics of setting one up are simple enough but actually building out/maintaining the infrastructure the correct way can be a lot of extra work (2 DCs for redundancy, sites configuration, users, groups, initial GPOs). There are also licensing and CAL considerations (bare metal and hypervisor, both different), domain and forest options that can paint you into a nasty corner of you’re not careful, and a whole host of other things to think about and plan around. I’m not arguing that a domain is bad, on the whole I agree 100%. I just like to set the record straight that building a new production domain isn’t as simple as a lot of people would have you believe, and OP might not have the time to go through all that.

I feel like this is legitimately more true than a lot of people think. Say what you want about the average end user, but UX is a HUGE driver with regard to adoption and user uptake. You can have the best of everything else in your application, but if the UX sucks, folks just aren’t going to use it