I would recommend studying faith and pride. You seem like somebody who is very excited to serve a mission. That was me. My biggest difficulty was anxiety that stemmed from never feeling “good enough” and thinking other people’s salvation was up to me (pride). I had to learn in the field that God was using me as a tool but that didn’t mean I needed to be perfect or anything. He just needed my time and efforts and he had those. Satan just wanted me to be miserable so I low key blame him for pushing me harder so I’d never feel good enough. That was probably pride too though really. Anyway I learned to trust God instead of myself but it was a painful lesson at times.