No. Reliable, universal and contemporaneous traffic data is generally not open source. You’d need to find a source and populate it yourself (aka the Main Roads department example I gave).
I can’t do that for every place on Earth. I’m not even sure I can do it for myself. It’s genuinely a hard problem and if anyone has a global fix, I’d be curious to see them add it. Not being snide, actually curious.
Best route choices: possibly, but it depends on what you mean. Geometry is pretty easy. Inferring best route based on traffic conditions…see above.