When Uncle Rick called Nico di Angelo and Will Solace soulmates, it made me think back to something written in BOO:
"Nico had once read a story from Plato, who claimed that in the ancient times all humans had been a combination of male and female. Each person had two heads, four arms, four legs. Supposedly, these combo-humans had been so powerful they made the gods uneasy, so Zeus split them in half – man and woman. Ever since, humans had felt incomplete. They spent their lives searching for their other halves.
And where does that leave me? Nico wondered.
It wasn’t his favourite story."
I think this is a really important connection. Rick didn't say what he did about Solangelo just to make shippers happy. He's answering Nico's question by saying he's worthy of love. There is someone out there for him despite what anyone says. And by doing so, he is also addressing every queer person out there who also doubts finding love and companionship in a world that so desperately wants to tear them down.
Not only did we get a book where the tragic main character gets a happy ending, but also one that validates every queer person out there. Anyway, that's my TED talk, thank you.
Edit:
Here is the quote that Rick Riordan made during an interview. I'll leave the link to the website in the comments!
neil always choosing andrew over everyone and andrew doing the same after years of them feeling like they're everyone's last choice is something so precious