IPv4 vs. IPv6

nothing to do with ipv4 vs ipv6.

[quote user="wswartzendruber"]

...But Open vs. Moderate vs. Strict won't be an issue anymore with IPv6 because it doesn't even use NAT.

[/quote]

While you are correct, that IPv6 will eliminate the NAT problems, the Xbox currently is not (yet) IPv6 capable. Maybe a future dashboard update will bring IPv6 capability, but until then you need to continue using IPv4 and IPv6 in parallel in your residence.

Web based interface. A wireless router.

Hello, My name is Jesse. I'm an Independent Advisor and a member of the Microsoft community and I'd love to assist you today.

Does the hotspot have a web based interface or it's from a phone?

It might be that your ISP is using IPv6 and tunneling IPv4 via CG-NAT and DS-Lite.

While IPv6 is generally a Good Thing to have (as the Xbox One primarily uses IPv6, and even if you only have IPv4, it will use IPv6 tunneled through IPv4), you might want to check with your ISP if they offer you a "Dual Stack" connection with IPv6 and a
real public IPv4 in parallel.

There really isn't much you can do on the console itself, as it does check automatically what IP protocol your ISP provides, and if it's IPv6, then the console will use IPv6. If it's a Dual Stack, where you have IPv4 natively (not tunneled through IPv6)
and IPv6, then the console will use both, and if it's an IPv4 connection, it'll tunnel IPv6 through IPv4 through Teredo.