Most answers here are missing the benefits of a home Mac running 24/7 if you’re already part of the Apple ecosystem. For example, you can have it sync all your iCloud data (documents, photos, iTunes content) and back them up locally, then elsewhere outside of Apple’s ecosystem. You can also have it act as a local CDN for OS updates, whereby it will cache OS downloads locally so any subsequent updates will be super quick.
On the downside, I found native Docker on macOS kinda sucked, and just installed Ubuntu on my 2012 Mac Mini (now running Proxmox for funsies), but I have an old iMac to do the caching. You could probably virtualize and get both benefits, and I am considering moving to a new M4 mini for the power savings and sheer speed. That M4 Pro chip has absolutely incredible Geekbench numbers while sipping power.
The thing I liked about Plex over Jellyfin (or even Infuse) on AppleTV was the layout decisions they made that promoted a sense of place. From any screen, I know exactly where I am, and can jump to the right to scroll big libraries alphabetically, or jump left to move to a different folder. It makes perfect sense to my brain in a way other design choices do not. These changes make me a bit nervous.
One tip I’d offer is that for Infuse, pointing it to the raw NAS media folder is annoying as AppleTV doesn’t protect local image caches from being purged so Infuse has to recreate all the thumbnails from time to time and it is dog slow.
Instead, you can point Infuse at your Plex library file directly and all your artwork etc will persist instead of needing to be regenerated every so often.