> On the other hand, he was a traitor, and he betrayed the trust of a true hero
I don't know. I have a hard time with calling Chelsea Manning a true hero. While some of the information that she leaked was useful in exposing war crimes, there was a lot more that wasn't particularly relevant exposing military abuses, but was used by enemies to track down and kill those who were collaborating with the US.
> in order to put more unaccountable government power in the hands of people like Donald Trump
I'm not sure how what Adrian Lamo did would have given more power to Donald Trump. In fact, it's Wikileaks that ultimately wound up being critical in the election of Donald Trump; by dumping a lot of not particularly noteworthy private campaign emails, but which could be picked through and made to extend some controversies and conspiracy theories around Hillary Clinton, it was one of the key factors in getting Donald Trump elected.
While there has been some good, newsworthy information released on Wikileaks, it seems to have been corrupted by Russian influence, has a lot of alt-right tendencies including antisemitism (https://theintercept.com/2018/02/14/julian-assange-wikileaks... ); I think that overall, it has become a net negative on the world.
From what I can tell, Chelsea Manning meant well, did some good, but also did a lot of damage, including substantially raising Wikiseaks' profile. I think that whether to report the conversation with Manning to the authorities was likely a difficult one, but the concern about leaking significant amounts of non-newsworthy but potentially quite dangerous information was well founded.
> Did he commit suicide
I don't think that's been revealed; but his Wikipedia article reports on several past struggles with substance abuse. Based on that, and general statistics on causes of death at that age, suicide, overdose, or motor vehicle accident seem like the most likely causes (https://www.cdc.gov/injury/images/lc-charts/leading_causes_o... for the leading causes of death, https://www.cdc.gov/injury/images/lc-charts/leading_causes_o... for the breakdown of the injury deaths by cause).