Hi Sokki, Have you tried the Advanced Preference browser.casting.enabled ? See: How do I cast to a chromecast from Firefox https://support.mozilla.org/en-US/questions/1171141

Also, the extension: MagicCast https://addons.mozilla.org/en-US/firefox/addon/magic-cast/

I have no issues with my phone. All I ask is a desktop version cast support

Those answers didn't seem to be phone-specific. I can't test as i do not use Chromecast devices.

I don't think Firefox is going to start adding vendor-specific code to their browser, if the methods described do not work already. Depending on what exactly you are trying to cast, other desktop applications may do the same. Or are you just mirroring your browser window or desktop on the TV? In the latter case, Chrome + Chromecast extension is probably the only (at least free) way to go.

https://store.google.com/product/chromecast_apps

https://en.wikipedia.org/wiki/List_of_apps_with_Google_Cast_support (Not a huge list, but specifically shows PC apps.)

Maybe good enough: https://hensm.github.io/fx_cast/