I wouldn't say IPv6 is significantly complex; just that it's difficult at first with people who are so entrenched in thinking about everything in address scarcity than abundance, such as with subnetting. I've taught/trained Zoomers on networking in the military, by covering IPv4 and IPv6 simultaneously, and they didn't see IPv6 as much of a hurdle. In fact, subnetting is very often easier under IPv6, versus having to often use calculators for most allocations under IPv4. Meanwhile, when I was still in military (just a few years ago), networks were consistently being restructured from IPv4 addresses being shuffled around to skimp around scarcity and changes the size of various units.