Bitcoin Core was, until recently, the closest thing we had to something "official", because until recently, Core tried to represent a supermajority of its users.
I don't agree at all that "it's obvious" that Core 30 doesn't meaningfully increase risk. "These same risks", namely Core 30 officially sanctioning large file data storage on the blockchain, have certainly never existed before.
Running a different client does not change anything if the de facto standsard on the network is that data storage is an official use case. But forking will change things, because it reverses the official sanctioning into an official rejection of the data use case.
