"Bugs" go along with living, organic-decay-based soil (what you want). Having them may simply be unavoidable with soil. [Ask soil growers; I grow in coco]. In contrast, coco (or rather, good coco) is pretty much inert, should have no readily microbial-digestable components, much less food for insects.
I don't recall packaged soils being sold with claims of being insect-free. Am I wrong? What % of packages soil bags contain visible "bugs?"
You can get insect larvae hatching and eating roots in coco (and I presume also with soil). But that is why you should be using a B. thuringiensis (Bt) toxin product, mosquito dunks, etc. in your feed water, to kill the larvae; and you should be doing this with whatever medium you use, whether coco or soil.