The full translation of the clip of Gaël Duval provided by GrapheneOS:

There's the attack surface, on that front we're not security specialists here, so I couldn't answer you precisely, but from the discussions I've had, it seems that everything we do reduces attack surface.

However, we don't have a "hardened security" approach, we aren't developing a phone for pedo(censored) so they can evade justice. So there aren't difficult things to check if the memory is corrupted, really hardened security stuff that could clearly be useful for executives, in the secret service, or whatever.

That's not our goal, our goal is to start from an observation: today our personal data is constantly being plundered and that wouldn't be legal in real life with the mail or the telephone, we want to change that. So we are making you a product that changes that by default for anyone.

As a french speaker, I can attest that the translation is fairly accurate.

While I don't agree with the characterisation Gaël Duval makes here, I believe the statement from GrapheneOS here:

Duval and his organizations have consistently taken a stance against protecting users from exploits. In this video, he once again claims protecting against exploits is for only useful pedophiles and spies.

Is a bit disingenuous. It sounds like they do make some efforts to secure their device, but it's not their main focus. Theirs is to improve privacy first and foremost.

I would take anything GrapheneOS devs says with a grain of salt, as we all know that they have quite an adversarial relationship with... well... everyone. But especially other OS makers.