What storage devices to add in my new server?

At the moment, I am still using my Intel NUC for Unraid:
One internal drive (KINGSTON_SUV500MS240G) as cachedrive and 1 external USB SSD (Samsung_SSD_870_QVO_1TB)

A very small set-up (see attached .jpeg) but I am very happy with it. I could not do more, because...well, it is a NUC 🙂

Today (or tomorrow), my new hardware will arrive. This will be a PC, instead of a NUC.
I would like to receive some advise. Important: I am still NEW to this and not a heavy user (yet), so please bare with me 🙂

Just running 1 Home Assistant VM and a few containers (Adguard, Zigbee2MQTT etc.). Furthermore it is more about storing notebook backup and I want to implement Photoprism as an alternative for Google Photo's.

Of course, I want to do more in the near future, but that was impossibble with my NUC.

What would you advise to do:

1) I will need a new cache drive I guess, what would be the best choice? I will have the following slots available:

M.2 (PCI-e 3.0 x2 + SATA)

2x M.2 (PCI-e 4.0 x4),

4x SATA-600 (According to the specs of my motherboard: ASRock B660 Pro RS)

2) Furthermore, would I really need a Partity disk now? I haven't at the moment.
I could add that later, so I've read.

3) I will need at least one disk for storing data. I could just add my current SSD disk into my new PC I guess?
 

These are really questions for newbies, I know, but I couldn't find a proper topic through all these hundreds of topics.
As my new server is coming without any disks, I need to have some quite fast 🙂

What type of disks are good start with, looking at my motherboard specs?
I will keep using the system mostly for setting up Docker Containers and Home Asssistant VM's, will want to have a Windows PC as VM, and of course as a backup tool for myself and family members. 


In the near future I guess I will fill the SATA-600 slots, for storage I don't need every minute of the day.

I will have this hardware (with Intel Core i5 12500 Alder Lake Socket 1700 Hexacore 6 performance cores 3.0Ghz/4.6Ghz) today and therefore I am looking for "what drives to buy"


Thanks a lot for your advice for his beginner, so I can look for the best affordable disks as soon as possible.

 

After that, I will need to figure out how I can migrate my current environment instead of starting all over...