As many others I got also the Problem to import all images from my own Patreon. Mine just imported partly … but before digging around for days into this I found a creepy but working “workaround” for this issue.
I did a backup from my own Patreon with a Chrome extension
I mean it is super creepy because … just think about it… but It did the job. Btw. it worked with chrome and not with MS Edge (chrome based).