I've been keeping an eye on Transmigration System World Hopping BLs and so far most are incomplete..
https://www.mangago.zone/read-manga/the_villain_loves_me_very_much/
This is the completed one so far which is the closest to what you're looking for with MC collecting his ML's soul and going back to the real world. However I can't quite remember the ending lol. I put note that it was rushed but still a good read.
https://www.mangago.zone/read-manga/the_expert_boyfriend_snatcher/
This is another completed one but it seems like author decided to make it so MC exists in all the other worlds except for the world where his ML was gone..... A lot of complaints about the cropping and such but I still like the different arcs. I like these world hopping webtoons and don't really care much about quality since we don't get a lot of them (multiple Transmigration stories) in the first place
Multiple Transmigration BL List
https://www.mangago.zone/home/mangalist/2766638/
Thank you so much!!
Is there any transmigration bl where the one transmigrate comes back to his original world after the story he transmiger into completes, i wanna see the separation of the couple, please help!!