I'm assuming this is not an acceptable solution, but a CSV Import with the server-side script preference off

You can script a CSV import using N/task so this might be a solution. I've seen this used for currency updates that are only supported via csv. @dcrsmith

Thanks. I thought about that. I guess the M/R could put the CSV together in the summarize stage and kick off that task.

Yup. This is the example I came across when I was investigating but I would have built it as SS2.0 if we would have gone ahead with that project https://github.com/luk3ns/Currency-Update-NS/blob/master/CurrencyUpdateCSV.js