The arrs are pretty light weight; the memory use can add up when you run several of them with really large libraries alongside other projects, but otherwise I hardly notice them running in the background. You don’t need any sort of special hardware; this stuff will run on an old laptop you shove in the corner and ignore.

The part that really takes processing power is transcoding media between formats when streaming it to clients, but that’s Emby/Jellyfins job.