It’s possible that you have mealybugs on your African violets. See the following publications for information on how to eliminate them:

https://hgic.clemson.edu/factsheet/african-violet-diseases-insect-pests/

https://extension.umn.edu/product-and-houseplant-pests/insects-indoor-plants#mealybugs-1581111

It is difficult to say what might be affecting your geraniums, but a good initial treatment for insects on most houseplants is to clean the plants thoroughly with an insecticidal soap. This may solve your problem and help you avoid the use of chemicals. The publications mentioned above provide lots of good information about how to care for your plants and treat problems affecting them.

Your small flies may be fungus gnats. See the following link for information about this pest:

https://www.bhg.com.au/get-rid-of-gnats-in-houseplants