You don’t need 8 drives when they are 8 times larger than your current ones. I went from planning for 5+ drives to just downsizing to two drives in mirror. Then I can expand with another mirror.

Unless you need uptime and want to guarantee an SLA for your own services, you are much better off with a mirror or raidz1. Do regular backups (off-site, incremental) and don’t fear the disk failure.