They are pivoting to become a fabless chip company as of last year (the decision happened a few years back): https://www.wired.com/story/chip-design-firm-arm-is-making-i...

I'd also argue that while Softbank has capital ownership of the company, the leadership structure and how that capital is allocated is still done within the UK with standard board oversight. I know a few of the leadership team personally, and they have a wide remit, almost more so than a public company might do.