I don’t understand the problem. Google services work in Firefox pretty much the same way, yeah? Does Chrome integrate an authenticator app? If som you might want change your 2FA settings at https://myaccount.google.com/security . If you have an Android phone you can get push notifications on it, or you can also use third-party authenticator apps.
Oh, gotcha. I misunderstood and thought you were describing a Chrome-vs-Firefox difference specifically. Yeah, I can relate. I’m de-googling my life but I’m not sure I’ll ever be 100% de-googled. I’m taking it bit by bit. I sign up for new things with different email addresses now and occasionally I’ll change existing services if it’s possible. But there’s no way I’m going to go through my bajillion web site accounts and move them all.