i have not tested the jp version, HOWEVER, the en version works like a dream on steam deck. just add the installer as a non steam game, force compatibility to proton experimental (i am not sure if this actually does anything), then open the installer and install like normal (i recommend installing in the Z drive)

once that finishes, close the installer. DO NOT REMOVE THE INSTALLER FROM STEAM. instead just change its name to Heaven Burns Red and change the launch options so it points to the game exe where you installed it.

it runs quite well and since its mostly a vn i get around 3-4.5 hours of playtime. i do force the resolution to 1080p to get rid of jagged edges in 3d scenes