Using distortions without being too harsh?

I’ve been asked to write some music that feels like mandatory propaganda radio. The initial brief included WWII era Soviet songs with the idea of making them chiptune/lo-fi.

So far I’ve played around with a bit crushed/distorted piano, and a saw tooth with a Stylophone.

I’d love any pointers for how to make something crunchy, without creating too much ear fatigue!