This question is not about using the YouTube phone app or about the app at all. It is about general login to one's Gmail account via a desktop browser, and avoiding Google's use of the YouTube app on one's phone for 2FA.
Up until about 1 week ago, when I log into gmail from a desktop browser, I would sometimes be required to enter a 6-digit code that was texted to my phone. My iPhone could be out of reach, but I'd see the code on the notification, punch it into the desktop browser, and job done.
Starting about 2 weeks ago, it stopped doing that and instead asked me to fire up the YouTube app on my phone for 2FA. I've had YouTube installed on my phone for about 3 weeks. I often have a corded heating pad to sooth age-related ailments, so I have to unharness my self from that, carefully push back the folding chair, get up to get my phone, unplug it from its charging cord, which is kind of short, log into the phone, fire up the app, wait for it to do its startup routine, then reverse all of the above.
By the time I'm staring at the desktop browser again, I forget why I was trying to log into Gmail. As is typical for many people, that login is just one step of one thing I was doing, among multiple things I was multi-tasking between. Obviously, I would like to revert back to the more efficient 6-digit code that is texted to the phone. As described in "Troubleshooting" below, this is what I have set up in my Gmail profile settings for Security.
How can I ensure that this setting is followed?
I carefully looked at my Gmail account's "Security" settings. The 2FA shows only that "Voice or text message...Verification codes are sent by text message." Nothing about having me fire up the YouTube app instead, and at no time do I recall even seeing the latter offered as an option.
I searched through the settings for the YouTube app on the iPhone, but can find no settings that might allow my Gmail account settings for 2FA to be overridden.
I have already tried to ask this question here.
This question was closed based on similarity with this and this question. However, they are completely unrelated. The first is about how to access one's Google account, which I can do, and how to set up 2FA, which I've already set up. The second is about bypassing Google's login verification screen, which is completely unrelated to my question.