Yeah Cecile, I don't wanna sound rude, but you need to learn to interpret things better:
"I want to write, not yuri, but a different genre for my next work" = HER NEXT WORK will be a different genre.
"I already wrote the manga I would want to write for the yuri genre, Bloom Into You, after all. If I don’t build up a lot inside me, or go through more changes, I don’t think I’d be able to write another yuri series" = This new work is something I need to try before returning to yuri, in order to write a better and greater story than I did with BIY.
"Even if I write for a different genre, I think there’s a possibility that it will still have a girl-girl couple in it, haha." = obviously, because is her cup of tea.
All in all, she's basically saying I need to try this new thing for personal growth as an artist, otherwise I might wind up on a stalemate and never get better (I'm looking at you Saburouta) but she warns, as she loves yuri so much, even though in a different direction, it might wind up with yuri anyway. Totally different that your initial statement "I'M DONE WITH YURI".