Did you enable SSH on first boot?
If not - go to System --> LibreELEC and enable shh there.
Otherwise try to ping each machine to ensure they are "connected"
"169.254.194.171" that looks like a strange IP address an ofc there´s no route to the host if the accessing machine is in a completely different network.
169.254.xxx.xxx IP adresses are most likely given if the DHCP server couldn´t submit an IP to the machine (DHCP IP range low, DHCP disabled or whatever).
So I would recommend to check which IP (for example) your laptop or desktop has and probably change the IP of the LE device manually to something else if you are sure the connection (wired or wireless) to your network at home is fine. For windows machines the command to check the machines IP adress is ipconfig.
For linux based systems it´s ifconfig or ip a.
Let´s assume your machines have something like 192.168.1.29 you can´t ofc use the same IP on the LE machine. You have to use something different. I wold suggest some higher number at the end. Try: 192.168.1.180
Manually editing the IP adresses is done at the LibreELEC settings: LibreELEC Settings [LibreELEC.wiki]
Is there something I need to configure on my router so that the 5G WiFi can talk to the Wired LAN?
No matter which WiFi you are using....as long as it´s the same network the communication should be fine.
It´s simply the LE IP which is not given from your DHCP server. It´s an automatically obtained adress if there´s some DHCP error.
See: How to Fix IP Address Starting With 169.254 - Appuals.com
