How to set up local home video game streaming with two routers?

I haven't really done home networking since Windows XP / gnome only Ubuntu days, so rusty is an understatement.

Currently due to the layout of my apartment, I have my main PC in a bedroom connected to a gli.net Velica router, such then connects to the wall, which then connects to a TP-Link Switch (1), which is connected to the internet.

In the living room, where I want to stream to a Raspberry Pi that has Android TV (lineage os), I have the Pi and 2 Nintendo Switches connected to another TP-Link switch (2), which is then connected to another gli.net router, which connects to the wall and then to TP-Link switch (1) which is connected to internet.

How do I set up a local LAN network so that my computer can then stream to the Pi via Steam Link, Moonlight, Sunshine, or any other recommended option?

Layout

Bedroom

         • Wall connection (port 3)
     |
     ∆ Velica Router 2
     |
     § PC


  

Living Room

         • Wall connection (port 1)
     |
     ∆ Velica Router 1
     |
     × TP Link Switch 2
     |.               |.      |. 
    π              ™ Nintendo Switch 1&2



  

Electrical Box

          • Port 1, Port 3
      |
      × TP Link Switch 1
      |
     🌐 Internet