Any recommendations like Sleepwalker? https://storiesonline.net/s/52891/sleepwalker
There was also a story in the "Whateley" universe where the protagonist had a dreamspace-like place inside his head where he could change his surrounding like the protag of sleepwalker, but not go into other peoples dreams. Just his own space where he could train or do whatever while his real self was sleeping or just doing nothing.
Not really too close, but Gravity Tales has a Chinese story of a guy that can use his mind to explore options and then pick the one with the best outcome. This story is being translated, so only the first 400+ chapters of the 1098 are completed.
http://gravitytales.com/novel/godly-model-creator
Otherwise, I cannot think of anything like Sleepwalker.
Now that I think of it, the Touchstone series by Andrea K Höst has a talent like that. Among many others. I liked it, although it gets a bit surreal at times.
And, I think there is a character in Worm that has that ability -- but I may be confusing it with some Worm fanfic.