And then he immediately got all emo about that right after, yelling at his fellow Autobots and practically calling himself a failure:
But then, the first time we see him in "The Return of Optimus Prime, Part 1", before he hears anything about Optimus's body having been recovered, he's seen standing next to a statue of Optimus, looking up at it, and moping about how Optimus still haunts him and that he'll never as good a leader as Optimus was. Then, when he does hear about Optimus's body having been found, he refuses to heed Jessica Morgan's warnings about it being a trap and rashly rushes to rescue the body, recklessly getting his team infected by the Hate Plague in the process. Even though the episode was about Optimus returning and needed a big crisis to give Optimus a big hero moment to save everyone, they didn't have to also make Rodimus
both a Debbie Downer and a Leroy Jenkins in this episode, which undid the, as you mentioned, growth he underwent "The Burden Hardest to Bear".
But speaking of that episode, "The Burden Hardest to Bear" was even unkind to Rodimus in comparison to Optimus, since after 65 episodes of Optimus leading the Autobots into battle with the Decepticons, we never saw Optimus having to face the consequences of the damage caused by the battles his Autobots had fought against the Decepticons. Yet, in this episode, we see Rodimus getting yelled at by the Japanese Prime Minister and blamed for all the destruction caused by the Decepticons. How come Optimus never got chewed out by the U.S. President or any other world leaders for all the damage caused by the Decepticons during
his tenure? It's not fair that they made a story where Rodimus gets blamed for Decepticon destruction and while the same was never done for Optimus. Sure, Optimus didn't have to go through the same growth arc that Rodimus did, but Optimus was just as "guilty" of "letting" the Decepticons cause collateral damage as Rodimus was, yet never got unfairly called out on it like Rodimus was in this episode.