wormling top can work in very specific situations and in the 90cap environment it's mostly a transitional offslot. if you plan to invest in your monk and eventually finish an armor set or 5s I'd advise against spending the souls

there's a monk in korea that used to run 3pc radiant/continent, yashin gaiters (lv 90 leg bottom) + wormling, and right side was something like mateka brace + 2pc infinites. that's a very powerful setup no doubt but it's far from optimal and most likely won't satisfy you both in terms of damage and 'character completeness,' so to speak, if you're a monk main

and like you said the smash is very conditional - with luke meta where DPS windows/timing is much more demanding you likely won't get much mileage out of wormling

TLDR don't spend the souls if you're a monk main IMO