Getting the files to your server is just (the easy) part of the problem.
You can look at the uploads with
cd /var/discourse
./launcher enter app
rails c
Upload.pluck(:url)
That’ll show you the URLs of your uploads. Then you need to modify all of those uploads so that they have the new path to your new bucket. You can try searching for the remap command. I think it might work
I’m not sure what this means.