(I know that I should have just used a mesh network)
I have a router from my ISP, and it is placed at one end of my house.
My Chromecast, printer, and other IoT devices are connected to it. I recently connected another router via Powerline to the other end to get quicker speeds, and to get Ethernet for my PC. However, I can't print off of the second router's network, and I can't use the Chromecast virtual remote. The router shows up as a single device on my ISP router, and none of my other devices connected to it show up.
Do I need to put the router in bridge mode, or do I just need to mess around with the configuration of it?
Will the router support 5GHz still? (My ISP router is only 2.4GHz) \
Second router model: Linksys EA6350
Your network is behind a second NAT. You need to put your router in bridge mode if you want to have the dhcp and firewall disabled.
Honestly the best answer is to get a dump network switch and plug in all of the devices to it. From there you should configure the WiFi router as a dump AP.
Personally what I did was install openwrt on two devices and then setup roaming with 802.11r
Your router looks like its supported if your feeling brave https://openwrt.org/toh/linksys/ea6350_v3