In the manga, Deku stays at UA. His journey is centered around his experiences and development within the institution. There are no plot points where he leaves UA permanently.
Deku remains a part of UA in the manga. His journey and growth are centered around the institution and its associated challenges and opportunities. There's no indication of him leaving.
Well, in this type of fanfic, it may start with Deku and Uraraka realizing their feelings for each other which had been budding during their time at UA. The story could then show how they start to date secretly, trying to balance their hero training and their new relationship. There might be cute moments like them sharing their dreams and fears, and also some tense moments when they face villains together and have to protect each other, which in turn strengthens their bond of love.
Deku might be completely shocked at first. Since Bakugou has always been so aggressive towards him, he would never expect such a confession. He might just stand there, mouth agape, not knowing what to say.
He might cry a lot. Deku is very emotional, and being cheated on would be a very painful experience for him. He could also get angry, which is rare for him, but this situation would be so unjust that he might not be able to hold it in. He'd probably start to question his self - worth too, thinking that there was something wrong with him that made his partner cheat.
You can try searching for it directly on Wattpad. Use the search bar and type in the exact title 'deku and uraraka love after ua wattpad fanfic'. If it's a popular fanfic, it should show up in the search results.
Deku might be initially shocked. He's used to Bakugou's aggression, but an actual injury is different. He could be in pain and disbelief at first. Then, he might try to downplay it, especially if he doesn't want to cause trouble for Bakugou, because Deku is generally a very forgiving character.
Some teachers might initially be scared and give in to the student's demands. For example, they might change grades or give special treatment as the student asks.
Well, some might be really amazed. They could see a new side of Deku that they never knew before. His singing might show a different level of confidence or a hidden talent, so they would probably cheer him on.
Some characters might try to understand Deku's motives. Kirishima, who was close to Bakugou, would be angry at first but might also try to find out if there were any extenuating circumstances. However, many would be afraid of Deku, seeing him as a threat now that he has killed one of their own.