Unraid would be my first suggestion as well. But if you prefer something FOSS, check out TrueNAS Scale. (It is important that you go with TrueNAS Scale, not Core. TrueNAS Core is the continuation of the former FreeNAS, which is based on FreeBSD. Since it's not a Linux system, it doesn't support Docker. TrueNAS Scale is based on Debian Linux and much closer to Unraid, it has full support for KVM Virtualization and Docker containers.)