I can’t think of any situation where it’s helpful to use the word “obvious.”
The problem is that it implies universal understanding. If I happen to not understand a thing that someone else says is “obvious,” it can feel very disheartening.
Instead of “This fact is obvious,” I prefer to hear, “I can tell that this fact is true, because of this reason.”
Not only does that feel a lot better for me – it also helps me learn. The next time around, I’m more likely to infer the fact from the reason.
This particularly applies to social facts, like “this person feels this way” or “doing this thing will make people react like this.” Those are often hard for me to figure out on my own.
But I don’t think it hurts to replace the word “obvious” in other contexts, too. For controversial topics, it could help some discussions feel kinder.