Sorry dude, once I figured out what I was doing wrong I’ve been able to get everything to cook/upload for me. Seems like it deals with bad referencing/the names of the BPs for some odd reason. The only other method (which I haven’t tried) would just be to manually copy and paste your assets into the cooked output folder where your mod.info is and then upload it from the DevKit and see if that route works.
I was going to try that if nothing else worked. But the last thing I tried worked so I haven’t gotten around to testing it.