Writing is good or bad, if we assume an objective.
Like a realist painting is good if it accurately depicts the reality that it aims to, and bad if it doesn’t.
Or, a motivational speech is good if it motivates, and bad if it doesn’t.
Clickbait writing is good if it gets clicks.
Informative academic papers are good if they inform.
Emotional eulogies are good if they emote.
Granted, clicks are easier to quantify than to what degree a piece of writing informs or emotes.
Even for non-quantifiable objectives, however, you can ensure your writing trends toward “good” if you begin with an objective in mind.