WARNING!!! I highly suspect this is a rookie question but I’m not sure if I’m thinking right.

I have a 1Gbps ithernet connection. My devices are: Tenda SG108 1Gbps switch, 2x 100Mbps Xiaomi routers (main and wired repeater), 2PCs and smart TV.

My original plan was to connect main router’s WAN and one of the PCs to the switch. Second repeating router is WAN-LAN connected to main one and both Smart TV and second PC are connected to it’s LAN ports.

Until today I had 100Mbps internet going directly to the main router and everything else was connected to it. But as I upgraded I bought the switch to be able to have gigabit on my PC and 100Mb for all other devices. My PC is connected to switch and all’s good but main router as well as secondary one simply can’t connect to the internet. I reseated all my cables, tested all connections and the only scenario when my routers are connected to internet is when I’m connecting the main one directly to the outside connection. But this way I’m getting 100mbps.

Is it possible to connect existing routers to switch or do I need to buy one powerful gigabit router and throw my switch behind it?