So I solved the issue and here is how. A quick recap, I was not able to access Facebook from any browser. I was just able to access it from the Facebook App on iPhone and Windows. But of course I could not change anything in my Account Settings because it will take me back to a browser version of Facebook which will take me back to the problem origin again.
The solution to the "You must login first" or "Unable to login" is the DEACTIVATION OF YOUR ACCOUNT.
But you need to do some steps before that if you, like me, were not able to deactivate your account. Here are the steps you should take:
1- Log out of any Laptop, phone or tablet you have.
2- Delete the Facebook and Messenger App.
3- Delete you Safari Cache, History and Passwords. "I will come back to this point later"
4- Delete your Browsers Cache, History and Passwords on your laptops.
The above points WILL NOT help you log in again but they are just "safe steps" in order to be sure that everything is CLEAN.
For point number 3, please turn off Pop up block, Allow cookies from all website and turn off do not track. You have to turn off your Java Script.
So how do you log into your Facebook Account Settings to Deactivate you account?
Simply, you need to log into Facebook using the old Facebook Platform. This is not the same platform used when you log into Facebook using Safari. It is the old Facebook Platform that was used in Opera Browser. What you need to do is the following:
1- Install Opera, try opening your Facebook using it and see if it opens to the old platform as per the below photo: (or you can just search for the photo to give you an overview)
2- When you open your account settings, Sign out from whatever location you have signed into.
3- Reset your password. (If you have not already)
4- Try to deactivate your account. I wrote try because I could not deactivate my account on the first time I tried to do so. I tried like 2 or 3 times then it was deactivated.
5- Reactivate your account and login using your browser.
6- Everything should be working by now.
NOTE: I used a VPN when I tried the above steps. My location was set to UK and then UAE but I do not think it really matters since you only need to deactivate your account.
I hope whoever reads this will get help with this bug. Facebook should notice these issues.