I was paying attention and think the error of the “Adventure Guild” is more on how diversified it is in isekai.
Playing older MMO games you get Classes/Jobs actually in different places and they are the ones that train your character up. You are basically from their organizations adventuring around, or depending on the point of view a graduated student from there seeking a better pay. Even the place you get each job vary like how Swordsmen are trained at the city by knights and guards, priests and acolytes are taught at a church or temple and mages at The Academy.
There is some sort of unified organization but it basically only issues quests during Events so it’s painted more as a government agency hiring adventurers as mercenaries.
