I'll see your HxH and raise you by Dr. Stone-
There is no magic whatsoever, and the maincharacter only gets buffed up by remembering chemical formulas and physical equations and relying on an old man named Kaseki who gets ripped every time he gets excited about making something (there is a bit of rarely used sci if magic in the form of
but otherwise everything is straight up Mad Science).
The series starts with the MC having to outsmart a series of brawn people, but in the later arcs he meets someone on his own level of intelligence.
On a different topic, I recommend a manga called Planetes (https://mangasee123.com/manga/Planetes) about an imaginary first manned flight to Jupiter. (It was written by the same author of vinland saga)
