Weird examples to pick because Metroidvanias have become very popular in the west, as have soulslikes, so you'll find examples of both from western developers.For those of you who ask what is the Morrowind JRPG or the Fallout 1 JRPG? I ask what is the western Castlevania RPG? or the western Dark Souls RPG?
And it's not like Dark Souls invented the exploration-heavy action RPG - early FromSoftware games (King's Field) were directly inspired by Ultima Underworld, and some of that DNA is still in their modern games. If you look at UU as the root of Souls, you could say the western Dark Souls is Arx Fatalis. Or perhaps Deus Ex, since the imsim developed out of Ultima Underworld.
Where's the Japanese Deus Ex, btw? Haven't seen an imsim from Japan yet. Great genre.