Extremely late, because I am dying in this land of Work From Home Nonsense, but yeah that sounds fine to me. A generic environmental shield thing. I'll assume he only got this going on one that can be recycled as a plot device item later if need be and in the way you suggest (working with a semi-safe cursed item example to create something that resists).

He'll probably vaguely keep researching the concept of this though because dangerous magic is exciting to research.