It will prolly drill easier now that you have negated the heat treatment it once had with the application of heat from a propane torch
I've had some difficult jobs, but once you heat them up cherry red with a act/oxy torch, they usually loosen.
@ this point I think you are going to have drill this one out.
The pix makes it look shallow, if so, that is in your favor.
I have some carbide bits I keep for special jobs but they are easily shattered,
so caution is paramount and not to be used in a hand held drill motor.
A good jobbers drill used slowly with lube, and pushed hard, should drill it.
At least you have a good center point to get it started straight.
Do as you like,but I don't like easy-outs
They are for different situations.
If the bolt, stud or setscrew was stubborn enough to break off/strip, an easy out will get you in more trouble when it breaks off in da hole, and do remember they are tapered so it expands the screw making a better grip on the threads.
That Said:
I'd try one more chance of heating it up, & driving a torex bit in it while hot/heating,
and gripping the bit with a vice grip and working it both
BOTH directions,while hot.
if it moves either way, just a mere smidgen, it will eventually come out.
If it moves ever so little, stop and go the other direction,
you are trying to work it free, not muscle it out
Also, bees wax applied will act as a lube when hot.
Just be aware bees wax will flare up (ignite) so don't piss yer panties
