@toroidalcore My ISP is IPv6-native, and IPv4 is provided over a MAP-E tunnel, so to get IPv4 working you need a router with support for MAP-E. Domestic consumer routers support it, but e.g. Ubiquiti and OpenWrt only very recently gained support.
I pay an extra $5/mo for a public+static IPv4, otherwise you’re stuck being CGNAT where you get a pseudo-random range of ports forwarded.
$35/mo for 10 gigabit fiber.