No. Every atom of your body, the chair you sit in, the building you are in, the planet you are on has been around, in some form or another since the beginning of time.
If you could send back or forward in time, a person or a paper clip, it doesn’t matter (pun), there would be the two copies of that same matter in existence at the same time, and that is essentially ‘creating’ matter where none existed...................
No, it is two views of the same matter from two different perspectives. You can't say "at the same time" or simultaneous because time is dependent on the perspective.
You can look up in the sky and see a nice big red healthy star -- or be close to it and watch an exploding supernova. No contradiction in that. Same matter, two perspectives.
I beg to differ. Your existence and mass in the 4 dimensions are set (I believe we’re in agreement on this part). If you go “back” to an earlier period in time you will not exist in the current period. Matter and energy are going to be conserved in there somehow.
Now, you may have to be turned to energy and “re-written” on that past period, but you are going to disappear in the here and now going forward (barring consideration of “many universes” theory) and the net matter-energy budget for the 4 dimensions is going to remain balanced.
The question that would arise to me out of this is that you would alter the net energy balance of the universe. I.e. as a whole, the amount would remain the same, but you would be changing the concentration of it back on the time pathway at some point. How this would re-equilibrate and what that process would mean/do to the past and present would definitely warrant study before doing it.