What if I'm using a VPN? Could that be causing the 'moonlight switch error timeout was reached' error?

Yes, a VPN can interfere with Moonlight's connection. Try disabling your VPN on both the Switch and the host PC. Moonlight relies on a direct connection, and a VPN adds an extra layer that can introduce latency and connection issues. If you need a VPN, try using split tunneling to exclude GameStream traffic.