Jeff zone 8 N.C.

For the gnats in your compost get some "mosquito dunks" (donut shape or pellets are the same) You need to crumble up the donut shaped ones and apply them to your compost. They are made to kill mosquitos in water but will kill some other bugs too. They are a safe natural product that is an inert virus when dry that comes alive with moisture. The actual product you see in the package is dried corn cobs that hold the virus. Works great to stop mosquitos in ditches and other water bodies.
As far as other bugs you can spray a garlic water solution or hot pepper spray solution if you want a natural product.