His - Koisuru Tsumori Nante Nakatta (2019)

Both are similar in that the main character moves to a new place and meets a guy there who they end up growing closer to, through spent time together, and then falling for. Also, both cover deeper topics as well along the way.

Both are stories of teens coming of age and falling in love, set in beautiful seaside towns. ITSAY is a bit more dramatic and has a lot more going on in the background, but it is also much longer. His is simple, short, sweet and very genuine. Both are very well written and have great conversations about what it is like to fall in love and grow up as a young adult.