Dang, one night in a tent and he had the U-Haul packed and ready lol. Honestly though, Ryan feels like a better match for Yuusuke. That sort of Knight Errant lifestyle makes sense for Yuusuke but its not an easy life, and a partner who'd join him on those adventurers and inspire him to keep going works really well imo.
Also you're right, there's like **nothing** about Ryan anywhere. The story ends with the MC up and leaving everyone he's ever known to go live with a man on the other side of the world (and has been living with him for YEARS as of the epilogue), and there's just no mention of it anywhere.