Synology was my gateway to self-hosting. I agree that now, with the knowledge I’ve gained, they are overpriced, but for a “NAS with training wheels” I can’t think of much better for people with the money to spend.
I think there’s a place for Synology and I’d like to imagine with such a resounding amount of feedback, they’re going to avoid the proprietary crap for a while at least. I’m not saying they’re a good company or that they deserve praise for backtracking on a stupid idea, but at least I’m not as reluctant to recommend them as I was.
You cannot just buy any SFP module and have it work. Most ISPs deploy a “special” (at least compared to normal point to point fiber links) that lets them serve multiple customers out of one port in their office. This is called a Passive Optical Network and requires specialized modules on both ends. There are ways to make a specific SFP work as an ONT and by cloning certain identifiers from the ONT to make the ISP think their box is still there.
This is a lot of effort and from my research, could stop working randomly in some cases.