Hello there.
I had the idea to make a crossover arc in Geek's Guide. We already had a character from Witcher 3 in Asshai. It was my first idea, to bring Robert to the world of The Witcher 3, though recently, I've been addicted to Baldur's Gate 3. I am considering it as another option, but I will leave the choice to you.
Another issue was a romantic partner for Robert.
There isn't anyone good enough left in the world of ASOIAF by chapter 80, and I don't feel like writing about him with a younger female (like Margery). Which brings us to the crossover. In Witcher 3, Ciri is a possible partner, and in Baldur's Gate 3, Karlach. The idea of Robert marrying what appears to be a demon sounded amusing to me.
Alternatively, we could go with my first idea, which was to make Robert into the eventual, immortal ruler of the planet, but without a romantic partner.
Please cast your votes on my Patreon/ patreon.com/Samael61.