If you do not have a technical reason for having two subnets, the fix is easy.
Each of your routers is performing NAT, and each has its own subnet, which is not what you want. Instead of using the second router as an actual router, just use it as a switch. Disable its DHCP and routing functionality and then use its switch (all of the non-WAN ports) to connect to the rest of your network and to other devices near the second router.