The memory limit on Intel Ark is wrong. They support 64GB IIRC but largest module available are 48GB.

You should also pick DDR5 edition since it basically doubles the throughput and DDR4 single channel is already bottlenecking the CPU.

But you can just start the container on his PC, then the Server is his PC?

Just start a yt-dlp frontend on that machine that should have the files in the first place?