Turn down the temperature. Your iron is not supposed to be hot enough that your flux burns. Then add a LOT of liquid flux to it. Maybe even let it soak in a small puddle for like 10 seconds, wipe, and then re tin.
Damp sponges suck because they cool down the tip and let stuff resolidify. Use brass wool; The same kind used to scrub pots and pans.
Lead free solder is more sensitive to lack of finesse, lack of flux, insufficient iron quality, and wrong tip size. The 1010 does not look obviously defficient so I am going to guess your tip size is bad which forced you to raise your temperature too high. I only go to 350°C if I am soldering something like a penny with lead free and I don't let it sit at that temp since I can smell burning flux. I am normally at 250°C for 63/37 and 300°C for lead free. It also helps if your iron automatically turns down the temp on the stand but yours does not.
Use a 2.4-4mm wide x 0.5mm-1mm thick chisel tip for your standard. Or 3mm bevel/hoof tip. Unless your board is high density, you can almost always go double the tip size compared to the pad, and you need to for SMD drag soldering. Larger tips are needed to use copper wick too, even if the pads are small.
You want tips with large thermal mass and able to produce large contact area. You also want the tip to be as short and blunt as you can get away with for easy heat conduction.
Conical tips fail all these criteria. Stay away from them. They blow. I do not even know why anyone bothers making them except at the smallest sizes where the tip point basically becomes one dimensional.
