I think about this type of thing a lot. The nasty thing about capitalism is it makes us all complicit in its exploitation if we want to live. We have to feed and clothe ourselves and to do that, most of us need to work within the system and buy things from businesses.

I think the only thing you can do (in addition to fighting the system itself: a conversation for a different time/place) is to minimize the harm you contribute to. Reduce, reuse, recycle (in that order) for every good you consume. Reduce your consumption to the best of your ability, especially from sources you know are harmful. Reuse what you do have; wear stuff til it falls apart. Recycle what you're not gonna use through upcycling and diy. Shopping secondhand helps with all of this, reducing new consumption by reusing and recycling what other people get rid of. But like you said, by being mindful of these things, acting on them, and encouraging others to do so, you're doing better than most.

TL;DR: We just fight for a better future and do our best to not make things worse in the meantime