Managed to solve the problem past the recommendations made by tflidd and I am typing the solution here to probably serve others who may run into this problem.
fstab
#Windows-Partition
UUID=537FEF451930795B /media/win ntfs rw,auto,users,exec,nls=utf8,umask=003,gid=33,uid=33 0 0
Reboot
sudo reboot
Force NextCloud to rescan files
cd /var/www/nextcloud
sudo -u www-data php console.php files:scan --all
And your ntfs local external storage is back in business.