This is normal, and many people have this problem. In fact, things that are obvious to you may not even be noticed by anyone else. I haven't heard how supplements can affect the uneven growth of beards. Beard care may be more important. I have three suggestions:
1. Keep the beard growing and trim the beard on the right to avoid sharp contrast.
2. Use a growth oil for patchy beard to accelerate beard growth on the left. A beard comb and beard cream are things you deserve. Keep trying until you find something that works for you, then stick with it. Eventually you will have a complete beard.
3. The worst idea: Wait for the uneven growth of the beard to be covered by nearby beards.