I got my talks reviewed and re-submitted them today!
In case anyone is confused like I was, it seems that you don’t have to re-submit them. Instead you can go to https://sessionize.com/app/speaker and edit your existing proposal. Or just leave it as-is if it’s good. At least I think so - I didn’t see any instructions about this. (I didn’t know this and first re-submitted mine from scratch, but then it showed duplicates there, so I withdrew the duplicates.)