https://www.carhartt.com/c/men-pants?query=:relevance:allCategories:men-pants:shaft_height:Work%20Pants

Carhartt has a good selection and they last long.

I would certainly attempt to get to the leak. Especially if it's on a upper floor. In two years it could weaken the structure enough that your next bath will end up falling through to the floor below. Covering up and treating the mold you can see won't stop it for good it grows fas and you can get sick by the stuff you can't see/reach.

Hard water and bleach could destroy the silicone or rubber in the flappers enough that it could trickle into the bowl. If the flapper is brand new take a closer look at the O rings too.