[altairprime]

Desktop Firefox doesn’t use the Apple WebKit engine on the backend, so that’s up to the Firefox Desktop team to implement on their own (and tie into the OS native if available, which I suspect depends on you running the latest macOS beta, assuming they’re working on it yet).

EDIT: Which they’re not, per above.

[freediver]

Apple Pay does not work in non-Safari WebKit browsers on macOS as of Ventura beta 4.