This information comes from the new Zelda art book 'Master Works', with the game's producer Eiji Aonuma revealing there was a period during this lengthy sequel project when the name could have ended up being 'Tears of the Dragon'. Now, we'll add a spoiler warning from here because there were apparently concerns this title would "emphasize the Light Dragon".
Here's a translation, courtesy of Nintendo Everything:
Eiji Aonuma: "Letting it slip that the Light Dragon is Zelda would have been a problem, and this had an effect on the title too. One of the candidates for the title that made it to end was 'Tears of the Dragon'.
But it would be a bad idea to have the keyword 'Dragon' in the title, and we wanted to have dragon patterns in the logo, but decided otherwise. It'd emphasize the Light Dragon, after all (laughs). But nothing else good was coming to mind, and we were running out of development time…"
In the end, one person on the team suggested incorporating the word "Kingdom" in the title, and so that's how 'Tears of the Kingdom' became the final name, and the "dragons in the logo" was able to be used. The team also felt this new title still had a connection to the Light Dragon.
Even when 'Tears of the Kingdom' was finalised as the name, Nintendo decided to hold back on an official reveal to avoid sharing too much information.
You can learn more about the new Tears of the Kingdom: Master Works in our full book review here on GameParadise. Apart from the possible name change, this new book is filled with plenty of other trivia covering gameplay elements like the Ultrahand and the game's final boss battle.