I did this just recently. From 2011 to 2020 I tried to find every big to medium down move to see how much my strategy would lose if you did nothing. It really helped me determine how much to risk on any one position. Before I did this I was closing positions too early and not giving them time/room to turn back profitable. I have a smallish account so I'm still nimble - hopefully I'm not shooting myself in the foot.
...so, a MACD is typically set at 26/12/3, right? G. Appel himself would tell you that there is nothing special about those settings. What if 24/9/3 offered better results? What if 30/15/5 kept you out of (more) false entries but kept you in on (more) false exits? Wouldn't that be a good thing? ("Yes!") So, it's testing testing testing. (And so, way-Thumb's-Up on the whole tenor of this thread. "Let your settings earn themselves." ) And, RE-test. Repeat: "Nothing magic here. Nothing sacred. Past results do not guarantee future returns." And test and test and test.