NAS for the first time and setup backup

[Enquiries]

Hi, I have Macbook pro almost filled 0.75 TB and my spouse 0.5 TB. We both have iPhone and do not have iCloud storage subscription and stored all data in the local Mac. My major focus is backup of data to NAS drive. My previous Mac died one day and unfortunately few days later my phone broke and had to buy new phone with NO backup. Reason for me to start thinking about private storage.