Unless you need the storage density in your setup go for the 20tb drives.

I went with the Evaluation Version of Windows Server and Windows 10 Enterprise. I was following some tutorials Ehen i got stuck. I dont really have any ressources apart from the microsoft documentation. I just did some basic tasks. Here are some examples:

• giving the user a network share
• disable and hide some settings from the User or force some settings
• set a desktop background for all users
• disable USB devices or only allow some specific devices
• autostart some programs

And so on you can basically tweak everything via GPOs or registry edits.

Just set it up and take a look in the administrative templates from microsoft.

My active passiv pihole cluster helped me to understand clusters.

I learned how to use docker containers by setting up my minecraft server.

My homeassistant VM and OPN sense test VM helped me to understand hardware passthrough.

By setting up wireguard i learned how routing works.

I was experimenting with GPOs in a test active directory running completely in VMs. That way i learned some basic stuff about active directory.

I really recommend setting up a proxmox server or something similar for experimenting.