Ah yes, about that Beyonce's overdone, showoff, Christina Aguilera/Mariah Carey style singing... yeah, it made me cringe too xP
And it's not just the singing, it also changes the whole mood of the scene. CYFTLT is supposed to be a calm, soothing song. It's a serenade for lovers, not a national anthem.
It's also why it's supposed to take place during twilight moving towards night (Where's the "sweet caress of twilight"?).

And... this might just be me, I don't know, but I like more the idea that it's an external voice singing and not the characters themselves. In the original movie it's not really Simba and Nala singing the whole song, but rather a sort of narrator voice singing about how they're both feeling. The word "love" may not even be in their minds at that moment, it's just happening to them. They're not telling us in their voices that they're falling in love, they're SHOWING us how they're falling in love with a lovely song in the background about love.

In the 2019 movie, both Simba and Nala are basically screaming it themselves to the audience, "I'm falling in love with this other lion!!!", and it feels like it comes out of nowhere, no build up to it, no expressions to show it, it's just "Yay! I met my friend again! and now we're suddenly in looove!"... only to have a little argument and decide that was all for nothing and part ways before night even begun -.-