There are definitely differences, but usually they don’t matter from a simple address and routing perspective.
For example, there is no ARP in IPv6. Instead another protocol is used called Neighbor Discovery Protocol, which actually is done through ICMPv6. Therefore, if you blindly block all ICMPv6, your network may break.
Once you have a grasp on v6, it is much better than v4 because even the smallest common v6 network size of /64 is many times larger than all the addresses in v4. Every device can have it’s own global ip, so you no longer need nat at all. Everything can easily connect, assuming there is no firewall blocking it.