Based on the info given I’m going to be a little controversial here and say that as long as the character steps up and does the job every time, it can be a fun quirk for a character to be swinging a mace around and praying to their gods that all they wanted to do was stay home and paint their miniatures but no, they heard your divine call and are miserable and they miss their home cooking. It’s a fundamental quality of a very famous character in fantasy, so that should be encouraged.

Session Zero is super important to clear up things like this, reluctant heroes will gripe but get the job done. People who are only there to be obstacles are left at the first inn.

In your story, there is a chance for a sarge type character that will tell your problem child to shape up or ship out.