With a carbide bit, you do not need to analyze what is before you, and your chances of the hole ending up where you want it are much higher.
I'd use a carbide end mill if I could set up the part to be drilled in proper support on a drill press, yes. Controlled feed along one axis rather than trying to attempt coring a busted steel screw with an expensive carbide bit held in a battery-operated hand drill.
5mm's a small target for welding on a spud, particularly if the broken screw's been drilled into already. If it's stuck in an aluminum threaded fitting, way easy to overheat & melt the aluminum threads, maybe more. Only positive aspect is that aluminum conducts heat so fast a careful attempt just might work.