There is a thread where the FP4 even fails at being a phone 
As for their advertising, they don’t really shy away for praising their camera abilities. There is no star symbol with a disclaimer that says but please don’t compare these claims with other phones.
It’s fair to say that the camera can be better. Yes, it costs money to develop a better camera. And I think they will make this investment. Because they are now under performing, even by standards of 10 years ago.
There are also open-source cameras that tent to perform better as well, such as the OpenCamera. They can open-source it too, if licenses agree with that. Then it’s not just them developing it anymore.