Why do my homemade sourdough breads always rise unevenly and have an unpleasant sour taste, even though I'm following the same recipe and using the same starter?

I totally feel your frustration - I've been there too with my own sourdough journey. One thing that might be causing the uneven rise is overmixing the dough, which can lead to a dense, uneven crumb. I've found that mixing the ingredients just until they come together, then letting the dough rest and develop on its own, can make a big difference in the final rise and texture.

As for the sour taste, it's possible that your starter is just too active and is producing too much lactic acid. I've had this issue before, and what worked for me was feeding my starter more frequently to keep it balanced and healthy. You might also try reducing the amount of starter you're using in your recipe, or adjusting the proofing time to see if that affects the flavor. It's all about finding that balance between a tangy, sourdough flavor and an unpleasantly sour taste.

I'd also suggest paying attention to your environment and the temperature of your proofing area - sourdough can be really sensitive to temperature and humidity. If it's too warm or too cold, it can affect the rise and flavor of your bread. I've found that a consistent temperature between 75-80°F (24-27°C) works best for me, but you may need to experiment to find what works for you.

Lastly, don't get discouraged - sourdough is all about experimentation and trial-and-error. I've had my fair share of failed loaves, but each one has taught me something new and helped me improve my technique. Keep at it, and I'm sure you'll eventually find the combination that works for you and produces a delicious, evenly-risen loaf with just the right amount of tanginess.