The Ant/TV command was also missing for my Panasonic model TH-50PZ850U, and that model has been replaced by the TH-50PZ850 in the database. The TH-50PZ850 has the command "ChannelUp" mapped to the input source named "TV". This will work, but it will go up one channel if you press the same activity again. The dataset for the old model (TH-50PZ850U) had commands like "InputAntA", "InputAntB", "InputTuner" but none worked. I ended up teaching the sequence "TvVideo"+ "1" in RAW mode to a command I named "InputTV" which I then mapped to the input source named "TV". In your case (since you don't have the remote to teach it), you could map the "ChannelUp" command to the "TV" source input and live with the minor drawback. You could also map the "TvVideo" command to the "TV" source input, and add the missing "1" command using the activity Start/Exit custom actions. In this case, if you hit the same activity again, it will bring up the TV input menu. You could also use the activity Start/Exit custom actions to issue the full sequence (TvVideo+1) and map a dummy command (a do nothing command) to the "TV" source input.

Note: To access, the Activity Start/Exit macro features, review the settings for the Activity (under Activity > Settings), and select "Yes, but I want to add more control of options and devices for this Activity". It will go through the setup again, just click next/save a few times until you get to the custom actions configuration page where you can add sequence(s) of command(s) to run at Activity start and/or Activity exit.