Bluepoint can work with the same Xdev, Japan studio people who helped them make SOTC and Demons Souls. The were the majority of the programmers
Yes, they could work for a Japan Studio (now Team Asobi) leaded game again but I see Team Asobi working alone on smaller games like Astro Bot, and Bluepoint working instead as one of the many teams who work on a big AAA game leaded by somebody else.
XDEV (a.k.a. External Development) mostly works managing external teams who make 2nd party games, plus also providing internal or external support/outsourcing teams for both 2nd party and also internally developed 1st party games.
In games like GoWR, XDEV -in this case their Santa Monica team- managed the support that different internal and external (outsourcing) teams provided to SSM mostly in the art area (character art, envorionment art, lighting, UI, animation, vfx...), with teams like Bluepoint and like a dozen external art outsourcing teams.
Then there's also PlayStation Studios Creative Arts, an internal Sony team that in case of GoWR provided help in Production, Art, Motion Capture, Animation, Programming, Music, Sound, R&D, Operations...
Plus there's the internal global PS Studios teams who work in all teams regarding Localization, User research, marketing, operations, QA, Compilance, Release Management, Tools & Technology, Finance, Marketing etc.