I’ve recently had to move my office into my home. I need direct Ethernet access for all of my work needs. I’ve been connecting directly to modem, but just moved my home office to a room where I only have the xid-p “cable box”? The only available port is hdmi. Can I use a Ethernet to hdmi cable to access internet that way? Again, WiFi not strong enough for my needs.
No. You can't connect to the internet through that port.
Some tips for improving WiFi performance;
There are other options. Google for WiFi repeaters / range extenders, WiFi mesh systems / pods, powerline ethernet adapters, MoCA adapters. Good luck !