Not wishing to undermine the central point, NAT for v6 is a thing. The point of the article is that it's not "NAT by default" the way home IPv4 is because so few places worldwide get more than a single IP per customer: The NAT is not there in v4 for security, it's to provide for multiple devices inside the home. Or, in the case of Carrier-Grade NAT, to manage multiple customers, behind a small pool of v4.
NAT doesn't exist to be secure. If it is, (and that is debatable because NAT busting is a thing) then, it's a side-effect.
NAT for v6 is not common. If you use ULA, you'd possibly use NAT for v6 in some circumstances.
Just to nitpick a bit. What people typically mean when they say "IPV4 NAT" is Network and Port translation. My 192.168.0.1 internally becomes 172.217.12.100 and my port gets converted to something that is tracked so that the return packet can find it's target.
In IPv6, Prefix-Translation is similar, in that the /64 prefix is translated 1:1 - but the /64 Host address is (in my experience) left alone - so that renumber a network becomes trivial when you change ISPs - you just just change the prefix.
I don't actually know if "IPv4 NAT" behavior even exists in the IPv6 world, except in the form of a lab experiment.
Why would you not use ULA if you have a network with multiple machines?