Unrelated to that but any reason for going RAID 10 instead of something like RAID 5? XOR is pretty optimized to the point you’ll probably saturate memory bandwidth easily and you get more capacity.
And for weekly backups: I do hourly ones to an on site server, and daily to off site.
Proxmox makes it really easily. Also, setting retention rules helps: 12 backups hourly, 14 backups daily, 8 backups weekly, 6 backups monthly