Not much more complicated than IPv4. There are more bits. The addresses are longer. It's not hard to grasp if you understand the prerequisites to understanding networking in general.

That applies to pretty much any reasonably complex idea. A new system requires effort to understand it. When you've expended that effort, it's not complicated anymore.

I don't understand this sentiment—as if learning IPv4 was enough work on your part, and now you're entitled to networking protocols never changing anymore.