Hataraku Maou-sama!, Kono Subarashii Sekai ni Shukufuku wo! 2 Recommendations
Both feature part-timers.
Both features a plot where a hero is sent to another world to live in a new culture.
Both feature a high level of actual enjoyable humour.
Both main characters are enthusiastic, to say the least...
Both have a group of friends predominantly causing drama for the main character.