To me it feels a bit sad for Dior by the end of the story, Yoshiki still holds a stubborn mindset of not going to the other world even if it is less permanent. I felt that he could have treated going there as a vacation instead of resolutely denying wanting to have any association with the other side. Dior is most pitiful due to how he wants to be Yoshiki, he would gladly go to Japan if he could, meanwhile Yoshiki doesn't even want to at the end of the trial period. I guess the story can only end short like that else if Yoshiki was willing, we could potentially have more chapters of Yoshiki adventuring to the other world and learn more.

I felt like when the MC went to the other world as a trial it was like the MC had a one (technically several) night stand during a vacation. But wasn't planning on continuing the affair.

Also on the soulmate part, I was half amused with how somewhat "realistic" the MC was about the concept of soulmates (at the beginning) since soulmates didn't exist in MC's world. But I disliked how the MC was suddenly affected by the "soulmate phenomenon" when he accidentally took a step into the other world. It felt very druggy and forced, like he was doused in Amortentia (Harry Potter love potion) with how suddenly MC felt all hot and bothered by ML