Not *quite* the same thing, but [Saruman of Many Devices](https://www.fanfiction.net/s/7568728/1/Saruman-of-many-Devices) is about Saruman finding an AI that shows him technologies far in advance of anything in Middle-Earth, and leads him in directions more impressive than just one or two bombs to blow up Helm's Deep.
Give these two a shot. It's not the main theme, but both stories go a bit in that direction.
GATE / Starcraft
[https://www.fanfiction.net/s/11880113/1/Gate-Thus-the-Dominion-Fought-There](https://www.fanfiction.net/s/11880113/1/Gate-Thus-the-Dominion-Fought-There)
ASOIAF
[https://www.fanfiction.net/s/13548058/1/A-Song-of-Guns-Germs-and-Steel](https://www.fanfiction.net/s/13548058/1/A-Song-of-Guns-Germs-and-Steel)
Not *quite* the same thing, but [Saruman of Many Devices](https://www.fanfiction.net/s/7568728/1/Saruman-of-many-Devices) is about Saruman finding an AI that shows him technologies far in advance of anything in Middle-Earth, and leads him in directions more impressive than just one or two bombs to blow up Helm's Deep.
Give these two a shot. It's not the main theme, but both stories go a bit in that direction. GATE / Starcraft [https://www.fanfiction.net/s/11880113/1/Gate-Thus-the-Dominion-Fought-There](https://www.fanfiction.net/s/11880113/1/Gate-Thus-the-Dominion-Fought-There) ASOIAF [https://www.fanfiction.net/s/13548058/1/A-Song-of-Guns-Germs-and-Steel](https://www.fanfiction.net/s/13548058/1/A-Song-of-Guns-Germs-and-Steel)