The Legend of Heroes: Trails of Cold Steel II [BLUS31597]

Getting the same thing.

First area is great 25-30 FPS and playable. Visual glitches happen periodically black textures, or incorrect textures on top of other ones, but those aren't that big of a deal.

Play until Ymir and the FPS drops to 15-17 FPS. The rendered cut-scenes drop to as low as 2 FPS.

Played until reaching Lunaria Nature Park to see if it was just Ymir, but the game is basically unplayable.

I've tried both BLUS31597 and NPUB31836 and the results are basically the same.

i5-4570, gtx 970
OpenGL

Game is still only running in Opengl so it's not very surprising there are issues like that the opengl backend isn't as advanced as the Vulkan one if i understand it correctly.
Anyway just wait for a fix and the PC version from XSeed and Durante shouldn't be that far off either.