How to organize access to backups (Acronis + Qnap)?

Question

Backup

Introductory:
- Windows 10
- NAS Qnap
- Acronis True Image 2020
I don't understand how to organize access to backups.
According to the instructions, Acronis suggests sharing a folder on the NAS and backing up to it, but if an attacker gets admin access to the system, or I let's say I catch a ransomware, they will have access to the backups and they can be deleted / encrypted.
I don’t understand what to google, all articles say the same thing - rummage through a folder, put backups there ...
P.s.
Acronis is unprincipled, you can replace it with any other paid / free software.

Answer 1

but if an attacker gets admin access to the system, or if I catch a ransomware

Create a strong password and grant write access to the NAS only to Acronis (by login and password).

Answer 2

Akronis seems to be able to send backup via ftp. You can raise ftp to Nas and put the backup there.