Far enough, its tough to make the entrance exam arc interesting, especially since kaiju izuku here got in via recommendation and we barely saw what that was like aside from a brief flashback. I have a couple of tips and/or interesting ideas that might help or not.
One thing I found to be VERY useful is to read other people's fanfics both here on Wattpad and on other sites like Archive of your Own or fanfiction.net that have similar story elements to your own and that can give you ideas on what to do. I had a similar issue with one of my stories where Izuku was supposed to create his own visions (Genshin Impact) but I didn't wanna involve magic. I was stumpted until I came across "Apotheosis" where Izuku made the infinity gaunlet by having the stones made of crystallized quirks such as AFO, lockdown, warp-gate and OFA.
Having Yaoriashi (wind guy who hates endeavor) stay with Izuku to become friend with him/her and having him take Mineta's place since Aoyama is needed since he's the traitor in canon. It also allows for some funny gags and for his to have an official rivalry with Shoto that actually gets put into the plot unlike in canon he just shows up and then dissapears.
Having Izuku not be in class 1A and having be in 1B, it would spice up the story a bit and add an extra bit of uniqueness to the story. It allows for some of the fan favorites get some attention plus it also add some uniqueness whilst also being annoying to write since you have to somehow get Izuku into the USJ despite 1B not being present in the slightest for that arc of the story.
There are stories were Izuku stays in 1A but some of his/her classmates are swapped like Shoto and Kendo getting swapped, Shiozaki and Shoji getting swapped, etc..
Again these are just me spit balling solutions I came up with when I wrote several of my fan-fictions such as my aforementioned "Villain with a Vision" story.