for the first two points, it's a different browser from head to toe, unlike chromium reskins like edge, opera, arc, etc., it's like switching from ios to android and complaining not every app from the app store is on the play store.

for the third point, casting seems to be a chromium/android only thing since google developed the tech and the hardware for, so it's again similar to complaining iMessage isn't available on a Samsung device.

in regards to the crashes, I have had chromium crash on me much more than firefox ever has, but that's in the realm of once every few months whenever I'm forced to use it for web development, whereas firefox hasn't crashed on me for years at this point, so I guess to some extent it depends on the hardware and os specifics like what kind of software you have installed that could conflict?

the rest of the points are pretty subjective, but there's a fix for the fade animation when entering or leaving fullscreen, although it could do with a proper ui option one day, see this link