you have alot of resources at your disposal never settle for just roulettes, dungeons, or fate to level especially at higher levels.

you need to logout in city hubs or townhubs usually places with the giant aetherytes this will give you rested exp bonus to your leveling

you should also be using food and any accessory buff you might possess as well as fc/gc exp buffs

you also have the hunt marks you can do from HW-END and some even said the beast tribes which are also good options

dungeons can be done with npcs as well they may not be as fast to complete dungeons but you still get the exp for the clear and you get all loot drops for yourself

fates should really only be done if you want to do them same with sidequests they are there but not required of you to do as a sole means to level up

pvp also rewards exp and usually has faster que times (even though i dont think pvp should have exp as a reward)