Gotta say that Vulkan in Dolphin and PPSSPP Is working reall good for me in 3.1. Tactics Ogre is actually silky smooth even at 2x resolution, Sonic Adventure 2 still has some ugly slowdown but its far improved. Even yaba Sanshio Lunar 2 played well outside of the (unskippable) video cutscenes.
With Swanstation I seem to be locked into JP region regardless of core region setting . Only got a Japanese pbp to play so far, any US discs send me to a japanese memory card/play audio CD menu. I had my bios files for all regions set up and working in psx-rearmed.