I do not think that time is anything more than what us humans use to measure how long things have existed. I don't think there's some clock of the universe we can rewind.
We needed a way to communicate in language cycles and how long things have been. We made time, right then. Humans starting recording things (or reading unintentional clues left to suggest something used to be different) and suddenly the universe wasn't just a constantly moving cog without any markings. We slapped dates on it and called it time.
I'm not sure on how to elaborate much more. I was trying to think of something to compare it to, something that can be measured yet not altered or not even there at all.
I don't think there's anything else that quite fits that like time does.
I'd love to be proven wrong, without doubt.
So you're suggesting that we invented increments of time. Ok, but how does that suggest that there is no such thing as time? This is similar to suggesting that distance doesn't exist and that we made it by creating a system of measurement for it.
Time is clearly real. We can measure the differences in time between satellites and systems on the ground. Time is faster for the satellites.
It's like you're suggesting that time wouldn't work the same way if we hadn't started measuring it which is absolutely nonsense and based on nothing.
Edited:
You can't go back, but going forward is possible with an infinite supply of time and work.
Prove it.