It’s difficult because we’ve all been the downstairs neighbor. I lived in an apartment that was built in the eighties and quite literally the walls shook when our neighbors stepped. We asked them minimize running in their apartment at 4am (they started their morning by running from the apartment all the way down the stairs) or drop weights but they refused. Looking back, I had wished they acknowledged our noise issues and let me know they were trying to make minimize it. I was sooo sleep deprived, we had to constantly remind ourselves the apartment’s construction was as much at fault and it wasn’t solely the neighbor’s fault. I suggest wearing slippers or avoid making noise before local city ordinance set time (Don’t blend, run laundry, or dishwasher during that time etc ). Let’s be real, you’re not the perfect neighbor because no one is! Just do you best to be respectful, avoid noise violations, and keep the landlord looped in. However, the neighbor Shouldn’t be harassing you either. As a current downstairs neighbor, we have.to remember the person above us has to live- sometimes you just have accept certain noises will happen or move!