So taking a look at these last 2 episodes post Mt. Doom exploding...
I really think Arondir was completely unnecessary to Season 1. He doesn't even show up once in these last two episodes, and as a POV character he has no real conclusion whatsoever to his 'arc', if you can even call it an arc. We just see him appear once throughout the 2 final episodes, and just as a 'cameo'...
I really don't get what kind of story they needed to tell for him and why they bothered having so much focus on his character when ultimately EVERYTHING that was necessary to the plot ended up being given to Galadriel instead once she arrives in the Southlands. Everything. EVEN in the role as the only Elf who is actively shown helping the Southlanders after the eruption.