I've heard great things over the years about Synology. I really would like to try it some day for a tiered backup solution, especially now that you've reminded me that the software is available separately. I remember reading that a long time ago and then I forgot all about it. I loved the original Windows Home Server for how easy it was to setup and use and Xpenology looks like it would've been even better.
Apple ? Anything and everything will be cheaper compared to Apple. External drive is also an option (I use one).
As a kid, I grew up with DOS and Windows in the 90's but when OSX86 was first available as a torrent in 2006, I tried it out as a curiosity and since then I've been using macOS as my primary OS.
It has been a constant frustration since then to settle on affordably priced hardware. After a year of OSX86 on my PC, I got a basic white macbook for an eye-watering $1100 in which I upgraded the memory and drive. Back then, it was the most amount of money I had ever spent on a computer. But I just couldn't keep it (buyer's remorse), I sold it a year later for $1000 and replaced it with a 12" Power Book and an Intel Mac mini that I upgraded with the fastest processor, memory and drive. The Mac mini didn't have discrete graphics so I ended up selling that after a year (macOS heavily relies on graphics acceleration for it's UI) and settled on another OSX86 build until I gave up and bought a top spec 2011 17" Macbook Pro. That machine died just as the two year EMI ended, and Apple replaced it with a 15" retina model. But that did not have expandable storage, so I sold it and went back to an OSX86 build until around 2016 when I built a 15" non-retina Macbook pro from replacement parts sourced from Powerbook Medic and Aliexpress. That machine is still operational today but it has started showing it's age (3rd gen i7). Apple Silicon has basically obsoleted OSX86 so I bought a base Mac mini a year ago with upgraded memory and 10G. But I just could not justify 80k for a 2TB upgrade from the base 256GB, so a 10G NAS made more financial sense.
As for why macOS, it's the system-wide scripting language that I've become heavily reliant on. Triggering apps/hotkeys with other apps/notifications. Multistep image resize/upload workflows are just a single click away. Most of all, it's these really cool stats in the menubar:
That's network speed, cpu usage, memory usage, disk space, disk speed all at a glance.