Just a couple thoughts (I have a mix of 2.5Gb and 10Gb):

• Mikrotik switches are a nice alternative to Unifi. Much less lipstick on the UI but reliable and fairly priced.

• If possible, you’ll probably want to use your own router rather than the all-in-one provided by the ISP. In my case, the router provided to me (Eero brand) did not even have a port fast enough for my service, and would have been an instant bottleneck.

• Options for 10Gb-capable PCIe adapters (what you might put in your server or desktops) are more limited (at least they were when I transitioned a couple of years ago). Intel-based network adapters seem to require less effort to get working (driver-wise) vs. some of the other 10Gb / SFP+ capable adapters.

Finally, you are correct: nobody needs an 8Gb internet connection. Aside from well-seeded torrent file transfers, you will never reach that limit (and probably still never). And, you’ll need an adequate storage backend to write that fast.