As you’ve already demonstrated above, it is a seki under Chinese (and other area scoring) rules, as Black attempting to capture any White stones would backfire with one of the Black groups dying.
The game is in a terminal position (i.e., no strategically worthwhile moves left to play and both players should pass), and I believe the correct ruling should be a seki in the top-right, and White’s three stones are dead in the bottom-right.
As worked out by @teapoweredrobot and @shinuito above, the key difference about Japanese rules is that determining life and death during scoring involves considering hypothetical play outs, while applying a different ko rule, which I wrote about in this post:
By the way, for people that like this sort of thing, I wrote about another case here: