my opinion is the best networking set-up is the simplest possible way that your system allows you to do. having two routers in a small set-up complicates your network. my suggestion is to stick to one router and if you have 2 isp's buy a router that supports multiple isp's and sell your two routers supporting single isp.
someone has jumped off the cliff for you already, thank that technician who had done that for you
kung naka fiber ka at sobrang bilis tapos konti lang units mo hindi na advisable mag doble isp pa o doble router para iseparate ang isp kaya na ang isang router na may dual wlan saka advisable lang ang dobleng isp kung paraten nagloloko ang primary isp mo para may backup ka pero kung hindi naman nagloloko sayang lang ang may backup isp
