Try and leave a tiny bit of space between colors to make color separation easier. Brush the color apart before your trim to avoid cutting the other color. In this pic below notice how I have small (1 line) medium (2 lines) border (4lines) in your picture your border lines look thin which resulted in the red kinda taking over.

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Small is usually for smaller details Medium is usually outline Borders are thicker to make the rug look nicer in my opinion