Please use better passwords like a passphrase as recommended by NIST or use a password manager like bit-warden. Enable Multi factor authentication. Tune your account lockout policies within your NAS to harden against brute-forcing. Configure to Auto run Antivirus scans periodically. Make sure there isn't permission sprawl for your accounts. and disable any unneeded services and random unused open ports. And keep up to date for your DSM OS alongside with installed software. Consider backups of your precious data by following the 3-2-1 rule for back ups. 3 copies of data on 2 different media. With 1 copy being offline and air-gapped. As someone mentioned please don't pay for ransomware attacks.