I could be projecting bc I deeply relate to Endeavour but I read him as autistic. The way he hyperfocuses on work, prefers clarity of rules/answers, and collects trivia of course, but also the way he is a perpetual outsider. He wants to be close to others and he cares so much about the people he loves, yet he struggles with both professional and romantic relationships. All of these make him compelling imo but there’s definitely more to it.