The WD MyCloud is very basic. If you JUST want storage it'll do the trick. If you want some more advanced features then I'd be looking at a Synology.
If you're set on $200, then I'd pick up the MyCloud. The Synology DS218j is similar price but doesn't include disks so you're looking at probably $350 or so, depending how you size the drives.
This page links to both the WD MyCloud and the Synology at the bottom.
https://www.amazon.com/Cloud-Home-P...ds=wd+mycloud&qid=1565280679&s=gateway&sr=8-2
You mention reliability - you cannot replace the drives on the lower end MyCloud. So if a drive fails I believe you're toast. But aside from that, I've used one briefly (set one up for an acquaintance) and I was impressed. For the money I think they're good.
I'm pretty protective of my data so another expense you may need to consider is an external drive to backup the NAS. I backup my MacBook to both my NAS and to external USB drives, and I also backup my NAS to external drives too. Time Machine to NAS is good, but it's not perfect. Not sure about others but I always like multiple backups.
You may also want to ensure you have wifi with at least AC1300 for the lower end 13" and at least AC1750 for the other Pro machines. Ethernet might be a good idea for the initial backup too. The initial backup to a NAS based Time Machine drive over wifi will be slow (depending how much data you have).
I noticed they have a dual drive MyCloud with RAID 1 for auto syncing the drives. Wouldn't this be sufficient for the actual NAS backup? Obviously I know that doesn't protect me from when I delete files myself since that gets synced, but at least from hard drive failure, yes? The 4TB option (2x2TB drives) seems kinda reasonably priced for that. Plus I could do Time Machine backups to it.
I just remembered my router actually has a USB port that, in theory, should allow me to attach any drive to it and share it on my network? It's an Archer C7. I guess I can research my options with that as well.
Also, as far as backups go, I also have a Crashplan for Small Business running at all times to backup my internal drive as well as my external drives when connected (plus Time Machine and some extra external drives to backup the other external drives... basically I try and follow the 3-2-1 rule). I'm not sure how well it would work backing up a NAS and if I'd have to use my Mac as the conduit between the two or if there is some fancy way I could get it to do it all on it's own without the Mac side, but I feel like maybe at that point it's starting to get into complicated NAS territory that I may or may not wish to dive into like I talked about before.