If you are looking for an "Episode 3" specifically, you are likely referring to the original 2012 OVA series , which has a different structure: Original Series (2012–2018) This version contains a total of 6 episodes Episode 3 of the Original
You have not missed a hidden release. Your DVD or streaming site is not broken. The story remains incomplete in anime form. Your only options for closure are the original visual novel or the older OVA series. If you are looking for an "Episode 3"
Some fans mislabel the second episode as “Episode 3” if they count the original 2017 episodes as Ep1–2. But officially, there is of the 2021 series. there is of the 2021 series.