The two cents are not literally monetary - your opinion is literally the two cents. You're contributing your understanding to the shared pot of understanding and that's represented by putting money into the pot, showing you have skin in the game. It's contributing to a larger body of knowledge by putting your small piece in - the phrases you suggest don't have that context behind them and in my opinion are worse for it. The beauty of the phrase is because the two cents are your opinion, everyone has enough, because everyone can have an opinion.

The lens through which you're analyzing the phrase is coloring how you see it negatively, and the one I'm using is doing the opposite. There is no need to change the phrase, just how it's viewed, I think.