Add the chopped red bell peppers, red chili peppers, red onion, and minced garlic to the slow cooker.
Pour in the granulated sugar, white vinegar, and 1/4 cup water.
Add the grated fresh ginger, salt, and black pepper to the slow cooker.
Stir all ingredients together to combine.
Cover and cook on low for 4 hours, stirring occasionally.
After 4 hours, use an immersion blender to carefully blend the mixture until smooth, or transfer to a blender in batches and blend until smooth.
In a small bowl, mix the cornstarch with the 2 tablespoons of cold water until fully dissolved.
Pour the cornstarch slurry into the slow cooker and stir well to combine.
Turn the slow cooker to high and cook uncovered for an additional 15-20 minutes, stirring occasionally, until the jam thickens.
Remove the jam from the slow cooker and let it cool to room temperature.
Transfer the sweet chili jam to sterilized jars and store in the refrigerator.