Also known as the longer title and original novel title of My Youth Romantic Comedy Is Wrong, As I Expected, we had already seen 2 seasons released. The second season was called My Teen Romantic Comedy SNAFU TOO!.
The first two seasons covered a full 11 Volumes of the light novel. The final Arc starts in volume 12 and the final book is volume number 14. This anime was known for cutting out a lot details. While I haven’t read the Novel myself to fully understand why some of the cast acts and reacts the way they do there is many background and minor events that helps us understand them. Below is the Promotional Video