It'll only work if you can direct play everything and depending on your ISP upload speed, you may need to transcode any remote streams in which case a Pi will probably burst into flames. A comparable option would be a micro form factor office PC like an Optiplex with a recent gen Intel processor. The iGPU in these works great for transcoding.

If you want something more serious you can do a custom built PC with a Fractal Design case (Define 5, 6, 7 or Node series) which are made to hold a ton of 3.5" drives. Again here all you really need is a newer Intel CPU and SATA ports (and/or an LSI SAS card).