Harry is actually a bit of a science nerd and argues in D & D about the incorrect use of fire. A physical manifestation of energy in the real world still obeys the law of physics and Harry knows this, personally as it nearly cost him a hand.
Harry already has his spell for generating an intense burning ball of light energy, he just needs to figure out how to make that coherent and directional hence the blasting rod.
Really what Harry needs to do is to make a blasting rod capable of emitting energy tuneable across the electromagnetic spectrum and coherently in the x-ray or ultraviolet spectrum. An X-ray laser requires a nuclear bomb to pump it up, I suspect the Eye was in fact a portable X-Ray laser generator pumped by magic and hate. Harry wouldn’t be able to generate anything like that power, but I suspect it might get through Eb’s shield.
Fun fact the US Military have a project exploring x-ray lasers it’s called Project Excalibur. Nice coincidence.
Being able to generate microwaves would also be of benefit, he can’t use a conventional microwave oven.