Levelling hasn't been relevant for years because it shouldn't be, nothing is interesting gameplay wise before you get your artifact and traits, even if you make things "harder" it wouldn't be interesting nor fun

Levelling was literally the main part of the game in vanilla getting to level 60 was a feat by itself and the levelling grind was more relevant than max level dungeons and raids, it's not the case anymore because the game recentered on gameplay and playing different characters, which makes for a way more convoluted and complex game as long as you're interested into actually playing it and getting good at it, instead of focusing on how easy irrelevant content is.

If anything, levelling is too long as it is, 2-3 days of brainless gameplay (no matter how you tune it) until you can get an artifact maxed and play the actual game, there are 110 levels now so fastening the pace at lower levels is just natural, if you can't accept it then maybe you should play what this game isn't anymore and kill furbolgs for hours on a vanilla private server.