Apple TV only showing me half the screen. I have tried changing HDMI ports, used a new HDMI wire, and checked all available options including reset, and factory restore, but this issue is still coming up

• Just for testing, try connecting the Apple TV to a different TV.
• Just for testing, try connecting a different HDMI device to temporarily replace the Applet TV in the setup.
• Power down (not sleep) the TV and Apple TV. Disconnect the power cable if needed. Wait a minute, then power up again.
• Check for firmware/software updates on the TV and Apple TV.
• If other equipment is in between in the setup (e.g. receiver), then verify those devices as well.

There is no setting for split screen on Apple TV, but there may be such a setting on the TV. Verify that.

See if you can adjust the settings: About overscan and underscan on your Mac, Apple TV, or other display - Apple Support

Although this is more for a full screen not displaying at the right size.

Did you try a proper Reset? Not Restart. In settings- System- Reset