A Student Just Proved Paradox-Free Time Travel Is Possible

Time travel always seemed infeasible to me on the simple fact that if (assuming as law) matter cannot be created or destroyed, the atoms that make up you now were already accounted for in a different time - in a cow, a blade of grass, star dust, whatever. You can't be in another time without duplicating those parts, or ripping them out of wherever they were

This is an example they give of how a paradox will resist being created:

> In the coronavirus patient zero example, you might try and stop patient zero from becoming infected, but in doing so you would catch the virus and become patient zero, or someone else would. No matter what you did, the salient events would just recalibrate around you. Try as you might to create a paradox, the events will always adjust themselves, to avoid any inconsistency

Could this hold true if it's something more public? Like the classic time-travel idea of going back to kill Hitler? That's such a global, public and world changing event that surely it can't just be somehow absorbed.