It's really a lot of trial and error to find a toothbrush and toothpaste that you can tolerate. I recently had to swap toothbrushes because the product I had been using for years was redesigned, and the new version was difficult for me to use. Likewise with toothpaste I had to go through a few options before I found one I was happy with.

And brushing with water is better than not at all! 👍️

As for how clean the bristles are, make sure you toothbrush can dry out properly after brushing. I always rinse mine before and after, and monitor for any mould at the base of the bristles. Generally it's recommended to replace your toothbrush every 3 months regardless of its condition.