A savant scientist with hyperthymesia has messed up and accidentally sucked him/herself into a wormhole. He retains the ability to float around his home world as a ghostly spectator as not all of his form has made it across so he is able to peer over shoulders and search for info other people are looking for.
He/she gets dumped into an alternate earth but everybody and everything has magic except for him.
The world is in a period of great peril as it is a global war where hundreds of feudal states fight each other.
The scientist must use his/her scientific prowess to survive in such a world where magic reigns supreme over the cumbersome use of natural phenomena.
I can DM a bit more world building if you need.
edit: rip to my idea lol but here's the changes to the idea
instead of feudal states, its basically 2000's earth but the scientist is in chile? so both his home-world and destination-world are both 2000's chile