By this I mean, what's the thing that would require the most amount of strength, or the least amount of weight lifted with maximum effort?

As in my max deadlift is 250, max bench press is 160, max overhead press is 120, the overhead press is what Im considering the most difficult because i'm putting in the same amount of effort as the other two, but lifting the least amount of weight doing it.

So far, the hardest thing I've found is holding a weight directly in front of you, arm fully extended, with palm facing the ground. I can only hold 25 pounds doing that with one arm - but idk if there's something more challenging, and would like to know.

Also nothing crazy like one finger deadlifts.

Meanwhile bruce lee could do that with 125 pounds with one arm what the fuck