Since you've logged in to most of the browsers then I think it's time for you to test and use their app and maybe that will change the result. I've just also read it somewhere years ago and tried that solution and it worked, hopefully it will work to you.
Did the app bypass the IP verification procedure? If it doesn't then I don't think it can solve OP's problem. OP can't log in because he uses a new IP, so the client he uses doesn't really matter afaik. CMIIW.
I'm not sure with that but based on my experienced, it did really solved my problem on this one.
It will work if OP is using the same IP address as before and previously logged in using that device,
otherwise Blockchain will detect it as new device and ask for log in verification, it's extremely easy to test that behavior actually if you have an account.
Users who reported that it worked must have a static IP or have had the same IP address when they previously logged in to the app.
I see.
I guess you two are correct with it, during that time when I'm able to solve my problem back then was probably I still have that the same IP so it managed to successfully logged in.
@OP, do you have any updates?