Am I sure that I've used Taildrop on my Android phone, Linux, Windows, Mac and Synology? Yes I am sure.
Maybe not great wording or arrangement of statements on that page since it seems to have stopped you in your tracks reading at that point, but you can scroll down and see discussion of using it on other platforms. What you're hyper-focused on is a subsection under the heading specifically dealing with Synology.
Geez, that was rude. I don't think assuming that the literally first requirement mentioned conditions the rest is "hyper focusing." It seems prudent to assume the rest are conditioned on it. It's not outlandish to assume you have to be on that style of network to use it, especially since the pitch is to enterprises for secure file transfer.
Taildrop is "a filetransfer for your personal devices", it only works if you have a Tailscale network transferring to QNAP/Synology is a nice feature. We all see thing from different perspectives it really helps to try understand why that might be.
Maybe not great wording or arrangement of statements on that page since it seems to have stopped you in your tracks reading at that point, but you can scroll down and see discussion of using it on other platforms. What you're hyper-focused on is a subsection under the heading specifically dealing with Synology.