I honestly don't see this as a bad thing, personally.
If it's anything like the first game, Hellblade 2's primary focus will be on immersion rather than precise action, so it makes sense to prioritize detail and fidelity. Besides requiring technical compromise, 60fps also takes a hell of a lot of extra work optimizing, which would delay the game.
It's also cool to see a game really push the limits of what the Xbox Series is capable of.
They may yet add a performance mode post-launch, like Plague Tale Requiem did, but in the meantime, I think 30fps is fine for a game like this; it certainly didn't inhibit my enjoyment of the first game.