If your case can mount the sata drives and your power supply has a 24 pin, four pin and enough sata connectors for your drives then all you need is a ddr4 motherboard, cpu and cooler.

If you’re stuck on off the shelf stuff then maybe a b550 and some am4 cpu, if you can mess around with weird shit there’s a bunch of odd sample intel cpu/motherboard combos floating around the aliexpress sphere.

Some of the am4 boards have multiple nics so that’s probably worthwhile for your use case.

wget -a website.url

It’s probably better not to try to preserve webcomics. It’s like the only bad form of art.