I can remember two numbers from 0 to 255, but four? Not in a million years.
Isn't there an idea that our working memory holds seven pieces of information? Which would be two of those numbers and change, if you consider each digit as a piece of information.
I also could have mentioned mDNS as a distinct subclass of DNS. That's most of what I use in IPv6 LAN stuff, personally, but I don't have a lot of subnets to worry about. Also I could have mentioned tricks like writing down a subnet prefix somewhere such as a .env script and using assigned addresses full of zeroes in that prefix like $PREFIX::1, $PREFIX::16, $PREFIX::cafe, or also, if you really want, and just miss dotted quads that much: $PREFIX::136.324.154.123 (that's been a supported address format for a few years now as long as it is on the right side of a :: shortcut).
I suspect that if the situation were reversed and we always had IPv6, and someone proposed a new IP suite where you had to use NAT for everything, and all hosts needed to have their addresses hand-picked (or served via a DHCP server that used an ugly hack to communicate with hosts that don't have an IP yet), you'd find that to be the "hard" one.