SSDs are coming down drastically in price so depending on when you create your NAS, you might want to consider NVMe SSDs instead of HDDs for the performance and power savings. I just bought 4x 4TB MSI Spatium’s and put them into a self-built NAS with ZFS raidz1 and I couldn’t be happier. It takes only 2 hrs to scrub 8TB worth of data.
HDDs are starting to become obsolete and I am honestly here for it. I think in the future SSDs will start to become much more economical. Currently they’re still 2x the price of an equivalent NAS grade HDD, but that’s better than the 4x just two years ago.