The NanoPi R6S looks like a potentially interesting OSMC box. It’s got 3 NICs so it’s more a mini-router platform, but it’s got HDMI and also an IR receiver.
Not quite as optimized for OSMC as the vero4k+, but might work well as a more powerful alternative to the RaspPi 4B for more money. No wifi though (but 3 fast NICs)
Also released, Pine64 have announced a QuartzPro64 based on RK3588 ( slightly better than the RK3588S ) but they only have dev boards so far, it’s not clear what the final SBCs will look like or price.
There is also an OrangePi5 (review ) based on RK3588 and maybe a BananaPI too (hard to tell, their website is confusing, seems like the are a board design firm sidelining as hardware vendor?).
But the existing posts on the Kodi forums (which are a few years old) tend to steer people away from RockChip due to them not providing proper android support and doing weird custom video stuff (making it hard to support Kodi). I don’t know if the situation has gotten any better recently.
So it seems the RockChip Kodi “port” lives at LibreELEC
I can’t see OSMC supporting Rockchip any time soon.