I hear you. I actually read it 3 times for me to get it. But after reading it from start to finish for the 3rd time, I understood why it ended that way. All of their previous lives ended in tragedy hence the continuous cycle of death. Both of them suffered because of unfinished business but faith was kind to them in their last chance of being together.
Sure, Dojin died of old age like his previous life but he died with no regrets because unlike the previous incarnation, he was holding onto the promise of finally being together with Yellow Dragon. He spent his life doing the things he liked, watch his niece grow up, see his family happy. It’s like the feeling of relaxing while seated in a bus stop waiting for the bus that will take you home or waiting for your parent to fetch you after a week of school.
He knows that after passing on he will finally, finally be reunited with the live of his life. There’s no rush, no uncertainty, no pain. All he needed to do was wait.
That's the thing he didn't live life, he was waiting to die, not living life but idling and accepting the day to day just for a promise, that's weird to me idk maybe I'm just not seeing what you see but I really hate how this ended that's all I can say... And rereading it is starting to make me dislike the entire thing. But thanks for the explanation it did help but just not for me I guess...
I wish I was like all the rest and cried at the end of this but I just felt frustrated with it because nothing really changed, it ended the same way it stared and I guess for most that's ok but for me he wasted his life waiting for someone who didn't show until he died, how was that living his best life because the author made it seem like he was happy to do so? No he could have and should have had a more fulfilling life looking after a niece dying without notice just to wrap it up with her dreaming he's happy? Idk