
Quick answer — Hiroki Sakai worked on Kaguya-sama: Love is War -Ultra Romantic- (Original Work Assistance), 【OSHI NO KO】Season 3 (Original Work Assistance), Oshi no Ko Season 2 (Original Work Assistance) and 1 more anime.
Hiroki Sakai worked on Kaguya-sama: Love is War -Ultra Romantic- (Original Work Assistance), 【OSHI NO KO】Season 3 (Original Work Assistance), Oshi no Ko Season 2 (Original Work Assistance), Kaguya-sama: Love Is War -Stairway to Adulthood- (Original Work Assistance).