Hey @casadacave,
well, my Spanish is no better than Portuguese NC 30 HUB9 - Falha em localizar caminho externo NTFS but this seems to be the same issue.
assuming you’re using an ntfs formatted drive for data for Nextcloud snap… that will be difficult, as permissions will not be set correctly even with ntfs-3g. suggest using ext3 or creating a samba share.
see removable media and permissions