One of the issues with multiple devices is networking. Transferring totally legit files for the Arr stack to and from the NAS can be a lot of data. Keeping it all in one system means your speeds up to that point are SATA speeds vs ethernet.

For the OP, one file with hard linking is my goal, but I only use Usenet. I rip anything that comes down with Tdarr to strip languages, normalize audio and rip to H265. If you do that with torrents, you will need to keep the original for seeding.