First time mini-home server

[pastaboy]

I am trying to build a home server for the first time and looking for some guidance to keep things low cost and heat/energy efficient. I am also looking to keep the footprint tiny. I was able to secure a M910Q for under $100 off a friend, so any suggestions on what parts to pick out and key software would be very much appreciated. The M910Q only has one SATA port and one NVMe slot, so any creative ways to expand storage is welcome too. I am not afraid of used parts or DIY!

 

A video of the expansion ports on the interior is here:

 

Budget (including currency): 300 CAD

Country: Canada

Games, programs or workloads that it will be used for: Docker containers for Jellyfin, rsync? for backups, torrenting Ubuntu, hosting some sort of proxy/anti adblock list, potentially some smart home stuff later on.

Other details: I don't have any existing parts at the moment, but wonder if there is a way to add even more drives. There are a host of USB ports, but I have read that USB hard drive enclosures aren't great for data integrity. Is there any way I could hook up 3-4 SSDs placed in some sort of 3D printed case?