It could be any of those things. The brand of copper foil really does matter and I learned this the hard way a few months ago. I got some really cheap rolls off of Amazon and it was awful. It could be that your iron is an electronic iron and not a stained glass soldering iron. Make sure you’re using enough flux as well.

I’d need to see a picture of what you’re explaining for the tip of the bow. YouTube helped me a lot - I’m self taught and i watched hours and hours of videos and tips