Try taking a few cuttings while you're hunting. Some euonymus root reliably but take their time over it.

Hi, welcome to GoY, E japonicus should be a dense , bushy evergreen shrub, grows to a height of 12ft with a spread of 6ft, so it sounds to me as if they don't like where they're growing, they're also only frost hardy, which means they can only stand temperatures down to 23f, if your temperatures get lower than this, it's probably why they don't grow so large, but as Steragram says you can take semi ripe cuttings in summer, give it a try, you have nothing to lose, and perhaps a lot to gain, Derek.