Issues and pull requests on the Yaru repository are often used for discussion, so this does not mean your icon is final. You can create an issue there to continue the discussion and include the Yaru developers.
Just wanted to note that the Ubuntu discourse is the correct place to start a discussion about changing something in Ubuntu. Some discussions, like those about Yaru, are better continued on the bugtrackers of those projects.
Edit 2: I 100% support this proposal btw; it’s a very easy fix which will make the difference a lot clearer for users!