Glad you got that sorted. Lots of folks have lost save progress (or entire saves in some cases) because of cloud issues. Disabling NMS cloud saves in Steam, and then making manual backups periodically, might be a good idea. Here are the Steam folders:
Steam on PC: %appdata%\HelloGames\NMS\st_<Steam64ID>\...
Steam on Linux:
$HOME/.local/share/Steam/steamapps/compatdata/275850/pfx/drive_c/users/steamuser/Application Data/HelloGames/NMS/st_<Steam64ID>/...
Oh, and a guy on the official unofficial discord maintains this NMS backup utility: https://github.com/weasel-nms/NMS-save-file-backup.