I just listened to both in full for the first time.
The sequence in "Let It Go" was great and the song fit, but the song kind of reminds me of a lesser, basic, snow-themed Firework? It does sound like it'd be on the radio. Maybe I'm missing something ground-breaking contextually because I haven't seen the movie.

But, as a stand-alone song it's just meh.
Young and Beautiful was fabulous and, like, I don't even listen to Lana Del Rey. This song was better and is far more deserving of Best Song in my opinion.

I'm slayed, actually.