I mean, newer server-grade models with independent actuators can easily saturate a SATA 3 connection. As far as speeds go, a raid-5 or raid-6 setup or equivalent should be pretty damn fast, especially if they start rolling out those independent actuators into the consumer market.
As far as latency goes? Yeah, you should stick to solid state...but this breathes new life into the HDD market for sure.
My dude, I understand your unwillingness, but docker is just a fancy new way of saying "install apps without it being a major PITA". You just find the app you want on docker hub or some other docker repo, you pull the image, you run it, et voila, you have a container. No worrying about python suddenly breaking, or about running 5 commands in a row to spin up an app (I used to do this, including the whole python rain dance, to run home assistant. I feel stupid now).
Decluttarr actually has a section to set up their container:
https://github.com/ManiMatter/decluttarr#method-1-docker
It's step by step, all you have to do is get docker installed on your machine, then copy paste that text into a file, and run the docker command mentioned in the same directory as the file.
Trust me, you want to learn this, because after the first 15 minutes of confusion, you suddenly have the holy grail to self hosting right at your fingertips. It takes me all of 5 minutes to add a new service to my homelab all because it's so easy with docker. And it's so ubiquitous and popular! TrueNAS SCALE uses docker for all its apps, the idea of containers essentially reshaped Linux desktop to be what it is today, with flatpaks and all.