You can use unsweetened frozen blueberries instead of fresh blueberries in equal amounts. Don’t let them thaw, just put them directly from the freezer into your batter.
Coating the blueberries in flour will help keep them suspended in the bread while baking, so you will have a nice distribution throughout.
Be very gentle folding in the blueberries to minimize streaking in the bread or crushing the berries
Oven temperatures vary and may need to be recalibrated periodically to ensure they are accurate. Make sure to check your bread at the lower end of the recommended baking time.