Journalists, regardless of the medium, do have to follow a code of ethics. Every country has one and for the most part they have few difference? Canada https://caj.ca/ethics-guidelines
The role of journalism is to answer certain questions: Who?, What?, Where?, When?, Why? and How?
We all know that several people can watch the same thing and remember something different. That is why journalists take notes, record and video-record the events they are reporting on. They are looking for the honest answers to those questions.
But sometimes a problem arises when the editor decides what goes on the air or get printed and what doesn't. He or she most likely wasn't there when the event happened. He has to rely on what he reads or what he is told. And he has to worry about what sells and what might get them sued.
So stories do change.
And sometimes a person's personal perspective or that of the higher-ups gets too involved with what gets published. That is biased. That is not ethical.
The simple solution is to get your news from an ethical outlet. They aren't perfect. But many reporters do try to get the story right or risk losing their job and reputations.