Isn't the extra 2 on Zen not a decoder unit, but rather a 6-way dispatch[1] with op-cache being used to kept the execution unit busy? Or was that the reason behind calling it a 5 or 6-wide depending on how one's may count it considering cache miss and all?

[1]: https://images.anandtech.com/doci/16214/Zen3_arch_5.jpg