bebopblues said

Firefox update now says that more than 1 device is required. I only use Google on my PC. I've disabled all apps and Google on my phone and I won't use them on my phone. Does this mean that I can't use Firefox anymore?

No. You can use Firefox.

Sync is an option. You can turn it off from here;

Type about:accounts<enter> in the address bar. [57+] https://accounts.firefox.com/settings

bebopblues said

Firefox update now says that more than 1 device is required. I only use Google on my PC. I've disabled all apps and Google on my phone and I won't use them on my phone. Does this mean that I can't use Firefox anymore?

A Firefox Account is not required in order to use Firefox on dektop (Windows, Mac OSX, or Linux), or on Android or iOS devices.

https://support.mozilla.org/en-US/kb/access-mozilla-services-firefox-account

I've already been using Firefox for years but when I installed the updates last night it told me that a Firefox account now requires 2 devises that are synced. I've tried everything I can to get around it but the problem is clear because the new info for accounts contains the question "Why does Firefox require 2 using 2 devices?"