Cryptpad does not seem to load at all and gets stuck at "uploading shared folders".

In my case it went on, but said then "This pad is not in your CryptDrive. Do you want to store it now?".
So I'd guess it's not there; maybe got a new name/URL at (re)upload, I don't know.
This message about storing it should always appear, that's a default feature of CryptPad. But the table indeed doesn't fully load. My guess is that it is potentially too large; as DarkStar_ already had issues due to its size.
For me, it's easily enough if only the last few weeks are mirrored on CryptPad. Not sure why he even migrated the existing table over. I expected it to only contain new weeks.