Getting a. PhD isn’t super competitive (speaking from the US), but if you aim to get a professorship at an R1 it’s somewhat competitive across the board. The program coursework vs undergrad depends on the program too— I would say most differ somewhat substantially though. For most humanities degrees you’re doing coursework for 2-3 years and teaching undergrads while you prepare for qualifying exams, then you teach and write your thesis for a few more. The graduate courses are often in seminar (circle discussion) format rather than lecture.