@dzinks You'd need two pfSense routers connected via their WAN interface.
192.168.1.0/24 can't exist on the same router with different interfaces.
You'd need to do a 1:1 NAT on both routers with different addresses poining to 192.168.1.0 for Production and Sandpit.
https://docs.netgate.com/pfsense/en/latest/nat/1-1.html
https://www.netgate.com/resources/videos/nat-on-pfsense-23.html