I'll Live a Long Life to Dote on My Favorite Stepbrother! (Saioshi no Gikei o Mederu Tame, Nagaikishimasu!)

Synopsis

A young man is reincarnated as Alba, the sickly son of an impoverished noble family in his favorite otome game. Alba is obsessed with his new stepbrother, the handsome protagonist Orsis. However, he suddenly remembers his past life and realizes that Alba is a minor character destined to die young just to provide "tragic character development" for Orsis. Armed with this knowledge, Alba is determined to use his gaming meta-knowledge to dodge every death flag and improve his health, all so he can live a long life and continue to shamelessly dote on his beloved brother.