There actually isn't a concise information on what it means in the novel and the translator didn't leave a note either
But it's mentioned
*mild spoilers for dialogue related to this*
'The pen name gave off a childish vibe'
'I used that when I was a college student with a lot of sensitivity. Back then, Hitele was popular, you know.'
So I assume that they may be talking about the meaning of words and from looking at google
Choi - her name
Kang - river but also strong/tough (can be used
Gong Du - to major/study a specialty to obtain a higher degree
So maybe it mean something along the lines of 'Great/Strong Scholar Choi'.
If not that then the only other interpretation for me is her using a name of another writer and comparing herself to them and there is a Chinese writer and poet Huang Zunxian whose courtesy name is Gongdu
And characters may find using an already recognized author's name as yours as childish.
Sorry if it's not exactly what you were looking for but I hope my view on it helped?
If anyone has a solid answer, please correct me ╥﹏╥
Can anyone explain what Choi Kang Gondu means? And what’s embarrassing having that as penname?