“The Catalyst of the Impossible” is Alexander Sedyh’s fantastic novel (the “Artefactor+” cycle), a genre of historical fantasy and portal travelers (“popadants”).
Saving the city of dwarves from destruction after an unsuccessful attempt to cleanse it, the main character has to use an old, untested portal. This failure helps him enter one of the techno-worlds—but closes the road back. He must find another path where Lexa will face new problems, new acquisitions, and new friends. It’s very difficult to unite magical and technical worlds without triggering yet another military clash—one that would destroy civilizations so very different.