Hello @Dali44 ,
Welcome to the forum!
I would recommend to start a one node with one disk. You can start the second and next nodes (each with own unique signed identity and own disk) when the previous one almost full or at least vetted.
You read it right - running multiple nodes will not give you more data, it will be distributes across your nodes, but in total it would be treated as a one big node. So, you will have a RAID on network level. If one node die - you will lost only this piece of common data.
With a usual RAID5/6 you have a higher probability to lost a whole array because of bitrot during rebuild after the one disk die. The last will be mitigated by zfs of course but with expense of more quick wearing of your disks and more slow storage in average.
If you configure it wrong - you can also waste a lot of space (in additional to the wasted space for redundancy in raidz), see Node using a lot of extra diskspace (ZFS)
See also RAID vs No RAID choice
If you would go for raidz anyway, then it is better to run your node as a docker container - it’s more light and doesn’t have a VM’s overhead for virtualization (the docker image uses your host’s kernel directly with isolation), and you can expand the allocated space with re-creating the container with all your parameters and changed allocation: How do I change values like wallet address or storage capacity? | Storj Docs
So you do not need to physically allocate space from the pool to the virtual disk for the VM.