Unfortunately I don’t have any answers to your question. I’m a rather casual observer with an interest but little experience. I only recently got interested enough to buy some books in the topic (and Sumerian history/mythology in general). It seems that the best source of untranslated cuneiform would be to physically visit the Department of the Middle East at the British Museum (not sure if anybody can make an appointment for the cuneiform study rooms or what though...)

If you or anybody else were to find a collection/library of digitized cuneiform tablets, I would be very much interested myself, more so if there are any notes or commentary.

It looks like they've got images of tablets from about 30 institutions, organized by time period. I've found a few with transliterations, but information seems fragmentary. There are also a fair number of entries without images.