export the data/media from media library
My current website with 500+ galleries is a custom development in Symfony that I am going to migrate to Wordpress.
What "WonderPlugin" offers is an importer tool where you can upload an XML that looks like this https://www.nrsoft.co.uk/wonderplugin_sample.xml. Probably don't need as many options but at least an album name and relative path folder to import the images from.
Let me know if this is something achievable in your roadmap before I decide to purchase your solution.