I’m not sure any version of TOS is airing on U.S. tv right now. I know TNG was running the SD versions of TNG last year when the channel was briefly unscrambled on my system. Maybe something will happen for the 50th anniversary? CBS seems to think streaming is where the money is now though.
Strange that. In the UK, CBS runs TOS Remastered in perpetuity on one of their FTA channels.