so, 300 dutchman. depending on the kinds of thrips you have, you are either gonna have the easiest time in the world, or like what the west cost of north America dealt this past season, a pain in the ass. I am lucky and have weak ass thrips around here, and the 2 times I have gotten them it was the easiest pest problem to deal with. once they came in on the space queen cutting I was gifted years ago, then this past year from some soil from a local store.
With the spinosad applications, you need to spray every 72 hours for atleast 21 days and make sure to saturate the plant, and drench the top inch or 2 of soil each time. thrip larvae live in the leaves, adults in the soil neem oil wouldn't really work on them as its not actually translaminar. a nematode spray is equally as wasteful, as they wont be able to eat the larvae, and will likely desiccate before killing an adult thrip it landed on. keep on drenching. Tanglefoot is less helpful than you would think for thrips. great for beetles and caterpillars though.
once you have beaten the thrips you can focus the gnats.
Gnats are easy to kill, but often get reintroduced in home and commercial gardens just because they are literally everywhere there is damp ground. they are one of the largest nuisance level pests in the greenhouse industry around the world. You get the yellow sticky traps, and hang them on your plants branches a few inches above the soil. you take a small 4 -8 ounce cup or jar and fill it with Apple cider vinegar(most effective) and a couple drops of soap you have green unscented palmolive soap(best to use IMO) underneath the sticky trap. the vinegar off gasses, attracts gnats. gnats get stuck to trap because they fly all weird, and the ones that go in for vinegar drown because the soap broke the waters surface tension, and smother's them. Xantham Gum(T drops) can also decimate and almost fully eradicate the gnat problem, but may( probably will) kill your beneficial micro worms(nematodes) and arthropods. There is a species of bactreria related to the ones in mosquito dunks, that works on fungus gnats. one of the brands is called microbelift I think.
since you said In Deach's thread how you have an organic soil blend, you can add so many badass little soldiers to your Integrated pest management army, that you wont need traps and sprays! If you are in the Midwest of the United states, order from a website called arbico organics. they have insects called Rove beetles, and predatory soil mites called stratiolepsis scimitus(formerly hypoapsis miles) that will eat all kinds of things. I use the stratiolepsis, the nematode 3 pack they sell, and a few other generalist predators in my lawn to harass fleas, ticks, and grub making beetles away so there is less pressure from those pests as I dislike spraying pesticides. My dog who passed a few years ago, was a grass eater, and he used to have occasional seizures. until we stopped putting down pesticides for grubs and then fleas. My boy lived 18 years because he had a pesticide free salad everyday for the last 12 years of his life lol
I believe you also said you brought plants indoors from outdoors. that's generally what we in the pest prevention game call, um, what's the term,.....a sure sign of a bad time. you just took all the pest/parasite organisms that were sheltering on or in your plants roots away from roaming predatory insects, and all kinds of disease pressure they deal with outside. making you the pressure on the pests.