Those aren’t different real numbers. That’s the whole point of the conversation.

Obviously saying it is not obviously true is false if 0.999... == 1.0

Can something be true and not obvious?

Obviously not.

Which is the point in using the word obvious, obviously. Namely, using it to feel superior or to not provide a better argument.

When I use the word, the point is to call out the fact that I think it's obvious, so if others don't, they can explain why. Not to forestall any discussion.

Anyone who uses the word differently is doing it wrong.