That smell usually comes from trapped food bits and moisture. Brushes with dense bristles tend to hold more gunk, so I look for ones with slightly spaced bristles and a shape that dries fast. Silicone options are popular because they don’t absorb odors as much, but they can be too soft for heavy scrubbing. I’ve settled on a regular bristle style that has a decent handle and hangs nicely. This 1 dish brush I got recently doesn’t seem to develop that bad smell as quickly—probably because the bristles aren’t packed too tightly. I still rinse it thoroughly and let it dry upright. Once a week I soak it in vinegar water for 10–15 minutes and it stays pretty neutral. Definitely better than the supermarket ones I used before.