If your EZ-out is hitting the burr before engaging I suggest grinding the tip to shorten it and allow it to go deeper.
I also strongly suggest you get some Kroil penetrating oil and letting it soak for a day or two before trying to extract the bolt.
In my experience, Kroil seems to be almost a miracle worker. I had a driver bit stuck in a frozen chuck that had defied all my attempts to remove it. Finally gave up and took it to a Milwaukee shop where the repairman took it to the back room and returned ten minutes later with it working freely. His secret? A little dab of Kroil! So I found the mfg on the internet and bought some.
Subsequently I found a pair of pliers and a six inch C-clamp buried in the yard. They were quite rusted and frozen having been buried for many years. As a test, I soaked them in Kroil for a day or three and after a little bit of effort got them unfrozen.
Kroil is effective but it is not cheap. It costs about $10 a pint from the mfg (Kano Labs), and a bit more from Amazon. It is not sold in normal retail stores. The mfg usually has a special for a liquid pint and a 16 oz aerosol for about $15. The liquid works best for really stuck parts. I think it also works better if you use a back and forth movement vs unidirectional motion. A larger hole and EZ-Out would give you more leverage and reduce the risk of it breaking again.