Aphids are soft bodied easy to kill insects. You do not want to poison yourself with pesticides meant to do major devastation. NEEM is as far as anyone should go for pesticides on their vegetables. NEEM is very gnarly. One treatment is usually enough. A second a few weeks later.
This is a fun fact; buy lady beetles and they will go anywhere but YOUR property. These insects are programmed to LEAVE the area they awakened. Best is to give your neighbors these insects as a gift? Then you will be more assured they will help you with your aphids and other soft bodied insects.
Don't spray NEEM during the day. I like dunking in a NEEM solution if the plant is in a pot and small enough to fit upside down in a 5 gallon bucket. When spraying, make sure you get all of the plant, the undersides of leaves, the stems the top of the soil. Do it correctly once should suffice. Keep checking, if more signs of aphids appear, 1 or 2 weeks later do another night spraying.
Plants take up pesticides. Neem smells horrid, works just fine, won't be poisonous to humans after washing your harvested vegetables. Other pesticides, forget eating your vegetables!
Pyrethrins are very very toxic, very effective...and guess what? They are from DAISIES! I use predatory flies instead these days. I have to deal with horse manure and flies...predatory flies work well. Just because something is labeled organic and pyrethrins are totally organic does not make them safe to use. LD50 for nicotine in tobacco is far more toxic than any synthetic. Lethal Dose in Half the population. The lower the number the more toxic the chemical or compound.
When we use pesticides we are putting a bandaid on a problem we should not have allowed to happen. I had a pesticide certification for every thing other than water for decades. I was never going to use chemistry in rivers or lakes...I rarely use even soap and water much less NEEM. Had to know what I was doing to tell bosses to go away and let me do my thing and be successful. When I had to deal with bosses. In Washington, it was illegal to use pesticides commercially without a licensed pesticide expert either applying or supervising others applying. I learned once you reach for a pesticide you've already lost and are just trying to recoup.
Aphids are an easy control. Before using NEEM, I use water spray and my fingers to control aphids. Squishy squishy. NEEM is my last resort and on brassica aphids usually the first solution I use for control when I find a problem. I would not use pyrethrins on vegetables...