We can probably all agree that a rear light or reflector is better than no rear light or reflector.
And I think we can get a similar consensus that a light is probably better than just a reflector with no light.
I am of the opinion that two rear lights are better than one, because they can and do fail or fall off and this could go unnoticed by the rider. I think there may be a majority in favour of that. At very least it's not a hugely unpopular view.
But beyond those points we are all in the dark and guessing, and there is no consensus.
Flashers good, flashers bad, bright lights good, bright lights bad. High Vis good, high Vis bad. There are loads of opinions, but they are all just guesswork, sometimes backed by arguments like "it stands to reason, dunnit". Nobody knows.
I wear a reflective band on my right ankle in winter, or for night riding year round. I just do. It's my little foible. I don't recommend it to others, they can do what they like.