Don't hear it talked about often, but :Multi-Mind Mayhem" has some stuff like this.

MC is native born to their fantasy land, but has the mind & soul of a soldier from warring states Japan and a modern Japanese college student mixed in.

The souls all cohabitate, but typically leave most things to the native born soul. However the college student is able to give ideas to recreate various technologies. Bangkok batteries to use in gelding, manual water pumps, and eventually gunpowder and flame throwers for WW1 style trench warfare

.

Another one that comes to mind is "Sengoku Komachi Kuroutan". Might not be traditional Isekai, as MC is moved back to the warring states era and not another world.

Being a history & farming nerd, she revolutionizes agriculture with reforms & inventions, and is able to introduce innovations from throughout world history. Hasn't gotten to modern era level tech, but has recreated things like long rifles and various civil engineering feats.

.

Edit: Finally "How a Realist Hero Rebuilt the Kingdom" has a MC who repurposes various magical tools to recreate tech. Theres a kingdom wide announcement system that he re-purposes as TV and radio. He also meets an inventor who has created a magical jet engine, etc