No, search and curation on itch.io works by inclusion. Include what you like, instead of trying to exclude what you don't like.
Viewing post in Anyone else got tricked?
Wait. What? "things you might like based on your rating, purchase, and download history"
Is having games on a collection adding to that as a hidden feature?
So having the collection "vn i hate" is a bad idea to improve my recommendations? (just kidding, but you see what I mean. I use private lists for keeping overview)
It does work.
If your recommendations show lots of vn, you do play lots of them. Or they match exactly your interests in other tags.
In the meantime, try this
https://itch.io/games?exclude=tg.visual-novel