WebGPU, WebHID and h.265 are all unsupported on firefox
that said, i still daily drive firefox with mostly no problems, but saying that it can do everything chrome can is just flat out wrong
this is by design mind you, chrome have a big enough market share that they can basically just add whatever they want to the web standards and all other browsers just have to try to keep up. i imagine that's part of the reason that chromium skins are so widespread
I feel like including WebGPU and WebHID is kind of unfair. They are both still in the working draft state as far as web standards go and are experimental. Codec support, on the other hand, is fair though.
To be fair, Chrome does generally render most websites faster and correctly. I have Chrome installed just in case of some webpages not working with Firefox. Now, that's not Mozillas fault, but from user standpoint makes Chrome more attractive browser to use.
By default, I doubt that Firefox is better at privacy than Chrome. Actually even worse than Chrome I'd say. But you can customize Firefox to be much more privacy friendlier than Chrome. That is the functionality Chrome lacks. The last time I tried out Ungoogled chromium, it sucked ass.
Websites actually loaded slower than on Firefox for me. And both had uBlock Origin installed.
I tried those fancy GPU stuff as well, almost nothing changed.