Oh my, I'm sorry for the late answer. For some reason, Itch did not update my notification bell (I leave the tool page open 24/7 in my browser).
Are you still having the 403 error? 40 days ago I had a version that gathered packages from PixelDrain, and they blocked direct download to the packages.
Due to that, I had to change back to Google Drive, with packages split in smaller pieces. This helped mitigate the issue back then.
Again, sorry for the trouble. I hope the tool is working ok for you now!