So I have an interesting client that has an already existing web application that would like to upload a large quantity of PDF documents into a library in SPO, and then add metadata to those documents from an xlsx/csv file (containing file name, and then columns with the relevant metadata for each doc).
I have been fiddling with Powershell to do it, mass doc uploading is working fine, but I can not seem to get the metadata to become accepted into SharePoint Online. Any pointers or previously written scripts/snippets? Many of the on prem commands don't work in O365, so I'm having to do it via Powershell/CSOM thus far.