It’s possible that in the multiverse, every moment of this current universe is happening simultaneously. So I wouldn’t be traveling to our past, but another version of us’ present, which just looks like our past. I could go there and cause that universe to believe time travel has been proven and then return to this one and nothing would be different.

Though I will admit that traveling in such a way does stretch the definitions to the point where “is it time travel?” becomes meaningless.