Cannot upload save file

I have a 300+ hour save file i am trying to upload to the cloud that will not upload. It will say it was successfully uploaded but when I try to import it, it doesn’t show up. I have been able to upload a different save file and it will show up, but it’s got around 2 minutes of play time on it.

I’m using PC (windows/steam)

I am having the exact same issue on my +700 hours save file on android.
I would be very grateful if this could be resolved somehow, so that I can backup my save and play on PC again.

As the poster above, I have no problem uploading another save. I also tried another Cloud ID, but it worked just the same only for all other save files, except my main one.

(Are there any options for me to backup from android, while I cannot use the cloud?)

edit: Game version is android 1.06
The file that cannot be uploaded shows up neither on android nor PC after the message that the file was uploaded is displayed.