Responses
Some aren't really inventing but bringing advanced knowledge from modern to the past..
Medical
https://www.mangago.zone/read-manga/the_black_haired_british_doctor/
https://www.mangago.zone/read-manga/doctor_elise/
https://www.mangago.zone/read-manga/i_reincarnated_as_a_legendary_surgeon/
https://www.mangago.zone/read-manga/doctor_s_rebirth/
https://www.mangago.zone/read-manga/the_crown_prince_that_sells_medicine/
Others
https://www.mangago.zone/read-manga/the_world_s_best_engineer/
https://www.mangago.zone/read-manga/i_shall_live_as_a_prince/
Any historical isekai manhwa where the mc just starts inventing futuristic items and other shit