Internet

I dropped all  X1 Gateway TV and DVR services and went to the Gig+ Internet service only via the XB8-T router over my existing coax cable lines. Before, I could connect to my Yamaha AV receiver (it has no Ethernet port or WiFi) from the X1 Gateway, and then to my Sony 4K TV from the Yamaha, all using just HDMI. Now, I can't make the same connections as the XB8-T only has Ethernet ports. Do I have to purchase some MoCA-type adapters?