I'm not an expert but even though "being critical of gender" is definitely part of radical feminism, there's more to it than just that and both aren't synonymous in my opinion. Rad fems believe women are a dominated/oppressed group in a patriarchal society; they claim women's bodies are being objectified by the existence of porn/sex work and surrogacy which need to be abolished; and like jiljol showcased, they have some very radical theses on societal structures and even people's sexualities. And of course since it is feminism, they logically focus on the women part of a problem (which differentiates them from liberal feminism which is kinda about... everything and everyone, and it doesn't make sense). Just to name a few things that are RF, but not GC.

Being critical of gender (roles or identities) first and foremost is not a movement, it's just a belief (as the Maya Forstater case made clear). The fact that we have to band together like that in order to make ourselves heard has kinda turned it into a movement I guess. Radfems share those beliefs but what I can also witness is that their personal spin on this differs from non-radfem GCs. For example, I hear a lot of radfems describing gender ideology as a male problem first and foremost and I don't even fully disagree here. But then they say things like "transmen/trans identified females) are just victims of the patriarchy, and while transwomen are oppressing perverts, transmen are misguided women whose trans identity is a response to the trauma of living in the patriarchy". I, a gay gender-critical non-radfem man, certainly don't feel like the abuse-hurling, yaoi-obsessed, gay-sauna-invading women are victims of the world I am supposed to be responsible for according to radfems. To put it simply.

I think that sums it up. There's overlap between radical feminism and gender criticism but that's it. Just because I don't believe that long hair and a dress makes you a woman, that doesn't mean I think that male homosexuality is a form of misogyny.