Can you provide additional details or screenshots?

The screen looks normal. Amazon is logged in with my name and their ads on the screen. I just can't click on anything. I did clear Firefox data and anything that I could find on their settings. Brave has no issue, and Google Chrome also no issue.

So I tried and I was able to log in and click things on my end.

When you say "force quit" you mean as in the process hangs and Firefox is completely unresponsive or just clicking things on Amazon doesn't work?

You could also open the Firefox developer tools (Control/command + Shift + i) before logging in to see if there is any errors or anything of note in the console.

Finally, are you going directly to https://www.amazon.com/ or are you getting there from a link, email, bookmark or something?