Hello friend!
According to your issue description, the PC fails to access the Internet through the LAN1 to LAN4 ports of the ONT. However, if ports LAN1 to LAN4 of the ONT are connected to a wireless router, the wireless router can access the Internet.
This problem is not caused by the hardware of the device. It should be caused by the configuration of the device. Check whether the working mode of the LAN port is correct.
However, because the home network parameters are planned by your ISP, you may not be able to provide them. Therefore, you are advised to contact your ISP for a solution.
Thanks!