One is termites born on wooden furniture (larvae are wingless, milky white, about two or three millimeters long, adults are winged, brown and black, a bit like big black ants with wings, more than one centimeter long).
There is also a kind of mite-like mite parasitic on wood products, which is white and very small (a little smaller than sesame, just visible to the naked eye) and climbs very fast.
Then there are bugs born in rice, one is small in white, the other is brown, with a shell of about two millimeters, commonly known as "Valley Dog". Do you see if you have old rice at home? That's how old rice got worms.
In view of what you said, according to my experience, I suggest the following:
1. Install a "trap" between the kitchen sink and the sewer, so that bugs will not climb up and the odor in the pipeline will not turn up.
2. If it's a mite or Mi Chong, you can buy a bottle of insecticide (the kind that kills mosquitoes and cockroaches), spray it on the place where the insects are infested, and close the cupboard door after spraying for an hour or two. Usually two or three times will be effective.
3. If it's termites, please only ask a professional team to prevent it. Household pesticides can only cure the symptoms, not the root cause.