If you could travel to any time period & place and have the ability to do something about a single event of your choice, what would you do and how would you go about doing it?

If you could travel to any time period & place and have the ability to do something about a single event of your choice, what would you do and how would you go about doing it?
Time travel to around 1895 to Fischlham, Austria. I would try to do something about a young Hitler & prevent WW2.
Or maybe to around 1904 and try to push him towards finishing his studies and joining art school instead of letting him become a major criminal in human history.
Sometimes a small push in a different direction can change the entire course of history.
I'd go on board the titanic in 1912, and warn the captain about the iceberg
Wait for a conclusive investigation regarding the COVID origin, then pick a shovel, teleport to 2019 and smack that Patient Zero XD
I would choose to prevent the assassination of President John F. Kennedy. This event had a profound impact on the course of history and I believe that if it had not happened, many other events and developments would have unfolded differently. By preventing this assassination, I would hope to create a more peaceful and prosperous world for future generations.