Im not using it so I wouldn't know but dont people still support their fav authors or something even if they are writing fanfictions? That's what I see especially authors on webnovel or ff.net
No one said about it becoming norm, as for legality and morality, well its not exactly my place to judge. People who pay on patreon also know all these i guess
Ai using makes it easier, but again your growth as an author and even your own creativity might get stunted.
I used ai to mainly check grammar and smooth things out, but ai later starts adding its own opinions and slowly the story becomes something else entirely if you overrely on it basically...
You can try mine if you are interested its a fanfiction of demon slayer called demon slayer the jin-esis
Just really trying out writing so all sorta critisms are appreciated