I love Ogeretsu Tanaka, she's one my favorite BL mangaka and out of all her works, I can confidently say that Happy Of The End is imo her most polished manga.
The writing is superb, the art style is as usual beautiful, her characters are complex, nuanced, endearing yet so tragic, and the combination of drama, slice of life, romance and psychological is so well balanced.
Tanaka sensei nailed the sad atmosphere, there is this ominous feeling throughout the whole story that we can't shake off ... still, we know Chihiro and Kaito will get their happy ending.
Plus it has one of my favorite trope : 2 broken people going through hardship yet finding solace and comfort in each other, healing together and slowly falling in love while living in cohabitation.
It's similar to one of my favorite BL Dousei Yankee Akamatsu And Seven but it also reminds me of A Stray Dog In The Night, Yatamoto and One Room Angel.
I already bought vol 1 and 2, now I'm patiently waiting for volume 3.
ETA : I bought vol 3 and completed this series. Amazing from start to finish. Now I'm on my way to watch the Jdrama.