How is Walter Lee in A Raisin in the Sun a tragic hero?3 main points or controls please. thank you

One can take this question into a variety of ways.  One way in which Walter can be considered tragic is due to the fact that he finds himself set against challenging circumstances.  On one hand, he is immersed in economic challenges.  His job is something that is unsatisfying both materially and spiritually.  His tragic condition is amplified by this.  Another level of tragedy would be that Walter seems lost in terms of his identity as the head of the family.  He wants to assert his control and guidance of the family, but in some levels he is impotent in doing so due to his lack of emotional stability.  His mother and wife are more centered and have a greater impact on the family than Walter does, especially so in the earlier stages of the work.  I think that another level of challenge for Walter is regarding the issue of being African- American in a time in American History where it was so very challenging to live.  Being Black in America at the time of the play possessed so many distinctive challenges that by its own recognition a tragic condition can be evoked.