Obligatory not a lawyer and this is not legal advice.
For 2D renders, the chance of legal action is next to none. The Daz TOS states you can essentially do whatever you want with renders, as you are not sharing any of the models themselves, and therefore not allowing others to obtain assets without purchasing them.
If you were to go around posting very publicly about how you are using pirated assets in your renders, and for instance you are using those renders for a game you have monetized, they could perhaps shut you out of revenue sources (ie, remove your game from steam, etc). But there is pretty much no way to verify whether the assets that appear in your renders were obtained legitimately or not, short of the author of those assets contacting you and asking for some sort of verification, or you announcing to the world that the assets were pirated. So, just don't do that, and you should be fine.