Enter for submit is too eager for Japanese (probably more languages?)

In Japanese, you type Hiragana and the input method would suggest or convert Hiragana into Kanji. Enter is required to confirm the Kanji. In the video, you can see there was a blue underline which means the Kanji is yet to be confirmed. But confirming it will trigger submit message in T3 chat.

Ideal behavior: it will confirm the Kanji but not sending the message. Reference video attached recorded from ChatGPT.

With some quick GPT check, it seems like it requires to also listen for composition event if you are using keydown for submit.