It's possible to run a virtual machine on ChromeOS, and within that virtual machine it's possible to run Firefox. This is not the same as running Firefox. A ton

It's possible to run a virtual machine on ChromeOS, and within that virtual machine it's possible to run Firefox. This is not the same as running Firefox. A ton of things (like drag and drop, video calls, and some aspects of rendering) are subtly broken. There is no hardware acceleration. Performance is atrocious; expect 15 FPS video maximum. There is a separation between Firefox and the rest of the system, with two filesystems and links opening in the wrong software. Accessing any hardware peripherals such as security keys, cameras, or microphones is unreliable at best. To anyone who has never had the misfortune of using a Chromebook: this stuff works terribly. Don't listen to anyone telling you otherwise. (I think it's actually a container rather than a virtual machine.)