How to ask Netgear to add Service Feature

I own the R7800 and works well, I am connected to a Draytek 130 modem and I wold like Netgear to add the option to allow UI access to modems from behind R7800

ASUSWRT achieve this by allowing an addition WAN IP address configurable IP route, but this option is not available by Netgear Firmwares?

I know I can use a seperate switch, but this feature built in would be more convinient and improve the user experience

UK Sentinel