Yeah questing, Gemstone Crab, NMZ, there are many ways to level quickly if you want that high damage output before starting slayer.
My favorite is questing > some sort of Crab > NMZ until like level 92-96 > then either slow rolling slayer if you don't need 40 million NMZ points, or using Dharrocks at nmz to 99.
tbh i have no clue about the crabbing or what nmz is lmao i havnt played in like 15 years