Change the "Filter rule association" to "Pass" and the "TCP/IP version" to "IPv4". Then it should work.For IPv6 don't use NAT but create a firewall rule (Firewall > Rules > WAN) permitting ports 80 and 443 to the fixed IPv6 address of your server inbound.
Did you try with a device connected to the "outside Internet", i.e. through tethering with your mobile phone?So called "hairpin" connections from inside to the outside address do not work out of the box. You need extra configuration for that. Let's get the port forwarding straight, first. So please try with an outside device.Second, I cannot help you with your IPv6 if you don't tell us how precisely your ISP is routing IPv6 down your line. DHCPv6? Prefix delegation? Static prefix or changing every couple of hours? ... and so on. We would need to know all of that.How familiar are you with basic networking concepts like this? Did you read the OPNsense documentation?
Does the system you named "Server" have the LAN IP address of the OPNsense as its default gateway?