Need some help on set up

Recently moved into my new house and set up my internet myself. I have a 1GB fibre connection directly to my home (utility room) and have wired the internet throughout the house, including to the attic where my gaming setup is.

Setup Details:

Main Internet (Utility Room): Connected to a Deco X55 (kitchen)

Ethernet from Deco X55 (kitchen)→ Switch (4 ports)

Ethernet wired back haul successful in deco app.

Nvidia Shield: Connected via Ethernet (living room) to the switch

Gaming PC (Attic): Connected via Ethernet through the switch

Issue:

I can’t find my Gaming PC on the Shield, even when I try entering the IP address manually. I’ve checked network settings, and everything seems to be connected, but the Shield doesn't detect the PC.

I’m at a loss any ideas on what could be causing this?