There is no historical evidence or credible indication that Albert Einstein ever invented a time machine or attempted to develop one. Time travel remains a subject of speculation and fiction, and no scientific consensus or breakthrough has been achieved in this area.
However, it's important to note that Einstein was a pacifist and known for his advocacy of peaceful solutions to conflicts. While he was a vocal critic of Hitler and the Nazi regime, there is no basis to suggest that he would have resorted to violence or assassination to address the issue.
Einstein was involved in political activism and humanitarian efforts, focusing on promoting peace, tolerance, and social justice. His contributions to society were primarily through his scientific work and his efforts to advance scientific understanding, rather than through direct political or violent actions.
Therefore, it is speculative to consider what Einstein might have done with a hypothetical time machine, as such a device falls outside the realm of his known interests, beliefs, and activities.