No. I think that was addressed with the yesh lo matirin arguments before.
I’m asking (and I know I could be very wrong) is:
the concept of bittul clearly requires two distinct identities. The thing being botul and the thing it’s being botul to.
Are strawberry ice creams botul to raspberry ones? I think not, because there’s not distinct halachic identity between them, unlike neveila and shchuta.
Now here, there’s milchig and pareve with the only difference being that the milchig might cause external people to violate a minhag/drabanan.
Is this sufficient to cause a halachik identity suffucient to start discussing bitul?