I recently had to verify my YouTube account with a phone number recently because it requires this in order to set a thumbnail.
Questions right off the bat:
1. Why do I need to verify to post a thumbnail that will take 1MB on their servers but not to post a video that will take 100MB on their servers and be public??
2. Why do I need to verify my phone number on YouTube when it's linked to my Google account which has a verified phone number and 2FA etc.?
In any case, it takes you to a CSS-less page that asks you to choose between getting an SMS or being called to get a code. I choose SMS and it doesn't work. It shows an error message with no description just "something went wrong". I try a few times and it keeps not working.
I then switch to the call, and guess what! I have tried "too many times" and will have to try again later. Call worked the next day, but geez, what a mess.