How do I get over the fear of high-voltage EV work?

That fear is not weakness. It is respect for something that can truly hurt you, and it will keep you careful. The techs who worry me are the ones who feel nothing near high voltage. You feel it because you understand the stakes. Fear turns manageable when it turns into habit. Learn the safety steps until they are automatic. The gloves, the lockout, the checks, the order of operations. When your hands know the routine cold, your mind can stop bracing and start working. Give it time and repetition. The voltage will not become less serious, but you will become more sure. Right now you are new, and new always feels shaky. Follow the procedure every single time, and the intimidation will settle into simple respect.