This was a few months ago so I can’t recall a lot of the specifics unfortunately.
What I can recall was using a 90w Ali Express soldering iron with a conical tip to solder a damaged original Xbox controller cable. The leaded solder seemed slow to melt on the tip but wouldn’t melt to the wire when I applied heat on the under side.
Sorry I can’t tell you more. I was looking to do some practice this weekend and wanted to know if I should be ordering a thicker tip or something.