OP, I know that feel and I couldn't find anything sold out there that quite met my needs. So I get my clothes customized at a local tailor. Was actually working on a pair of pants this month. I design em, the tailor gets em done.
I pick up pieces of clothes that I need for their utility and combine parts of them. For instance, for these pants; I got a basic lightweight pair of cargo pants, some adidas running clothes with those little parts that let air through so it can breathe and keep you cool, a pair of kneepads and some ballistic gel.
I intend to put the elastic, breathing parts right where the pants bend and stretch, like behind the knees, by the shins etc. place some of the ballistic gel on spots that you tend to fall on while running / jumping around etc. to protect from impact damange, and install the kneepads into the pants themselves so they're a single unit that you can just put on.
Also, I stitch zippers onto all pockets on anything I wear, because I'm fucking paranoid I'm gonna drop what I'm carrying if my pockets don't have way to keep them closed, which isn't too illogical to be honest. Plastic zippers work best and don't tend to jam easily.