This is a stock isekai series, so he's obviously going to have the usual cheat powers. I said as much in the Overlord thread, but quite often the only struggle is in (demi-)human relationships in these series. I suppose it's some kind of ultimate escapism. This series at least has a little bit more going for it due to the medical stuff. The author had to do that much research. However, this is still an average isekai series, at the end of the day, so it might not fly it tried to be two things at the same time, by going as in-depth as Cells at Work.

He can produce full molecules if he remembers the chemical structure. That's quite a tall step, though. If he could only produce raw materials, he would be often out of luck because more complicated molecules are no joke to produce. It takes more than a few test tubes. In fact, I doubt he would even know how to make them, most of the time. It wouldn't have been really necessary for him in his first life.