Welcome to the Strelets Forum. Please feel free to discuss any aspect of 1/72 scale plastic figures, not simply Strelets. If you have any questions about our products then we will answer them here.
Try spraying it with Plastidip transparent spray after the painting is done. It's transparent rubber that prevent chipping/flaking. I've been using it for year, without it I would not be able to paint soft plastic minis.
After this a layer of matte varnish is recommended as it's pretty shiny.