Love. Depression. Obsession.
She was a normal women. Nothing more than that. She loved her family as much as anyone would. But when one of her family, her husband, just disappeared, she couldn't take it. She didn't even know if he was dead or alive, what happened to him. He just disappeared. Depressed, she devoted all her time to finding him. The only clue she had was that he was researching an alternate dimension, so she picked that research up in hopes of finding him. The insane amount of time she devoted to them and her desperation to find her love, slowly lead her subconsciously replacing her husband with Ultra Beasts as the object of her love.
She herself mistook her devotion as love, and it slowly grew into obsession over the span of years. Because she couldn't find Ultra Beasts themselves, the obsession grew from being just about Ultra Beasts, to everything beautiful. And her indention of "beauty" was a bit fucked up. It wasn't about appearance. Only Ultra Beasts were beautiful in appearance. Because she had failed to get results, because things weren't going her way, she found things that did do exactly what she wanted to be beautiful. Anything she controls is beautiful and deserves her love, everything else doesn't.
This is just the backstory. The actual game is still there, you can play and see her there for yourself. This level of complexity is almost NEVER found in villains. Not only that, there is not a single "random" trait she has. Her past and the events she went through define her, like any real person. Her personality is a direct result of that past. She is often accused of being Ragyo ripoff, but she shits all over Ragyo, who was just a random maniac. Simply put, she is a great villain, one who easily shits on most villains in general. No Pokemon villain even comes close to her.