But that baggage is a huge part of the problem. Almost nothing you know about IPv4 applies when you switch to IPv6, and most of us found that out the hard way when we tried to make the switch. Leaves a pretty bad taste in your mouth.
Also a nitpick: switching is irrelevant here, that’s L2. L2 doesn’t even know what’s an IP address :)
There was some dude on YouTube that resurrected the first Ethernet bridge (which was built for thicknet) - I recall even that worked with IPv6.
This is exactly what I'm talking about. When you have problems with your IP network, that's the first thing you try and figure out, "what's my address? Why is that my address? Did it change? If so, why? Are other devices able to get packets? What are their addresses? Why can those addresses get packets but this address can't?"
The things I need to think about are precisely the things that changed radically. Firewall rules aren't the same due to prefix changes and no NAT. DHCP isn't the same, DNS isn't quite the same, distributing NTP servers isn't the same.
Almost nothing of what I knew about configuring my home router for IPv4 has transferred to IPv6 configuration.