>What happens if your ISP changes your IPv4 address?
Absolutely nothing, because the private IPs behind the NAT are agnostic of the public IP.
Actually, all your open connections break (including outbound ones, inbound ones via UPnP which is commonly on by default, etc.)
Actually, all your open connections break (including outbound ones, inbound ones via UPnP which is commonly on by default, etc.)