I'm looking to get a desktop PC that isn't too crazy expensive but heavy duty. I am not very tech savvy. My requirements are as follows:

Intel processor i5 or i7 8th gen. (10th gen would be unnecessarily expensive I assume)
RAM 16 GB
256 GB SSD
Ethernet adapter for wired internet connection
Ability to connect 4 displays via HDMI to show different screens on each display
Average graphics should be fine as this will not be a gaming PC but must be able to play full 1080p videos.

What would be the cost to build such a machine?

My other option is to get a ready-made HP/Dell PCs.