"Genetically Engineered" humans is an old, old Science Fiction concept. Everybody who ever proposes it overlooks the obvious problem with it, and it isn't any resistance from the general population or the rest of humanity, although that could be considerable.
It's the fact that it takes 15 - 20 years to get a genetically enhanced soldier starting with a genetically enhanced baby. And during that time your opponents can simply develop better weapons for their soldiers, train them in a year or so, and wipe out you and your genetically enhanced children. The entire concept is militarily inefficient.
Also, of course, there are limitations to just how enhanced you can make the humans: you can make the average, or even above-average - sized human body stronger, but you cannot make it as strong potentially as a machine made of advanced metals and powered by advanced engines: the limitation on the human is built in, the limitations on the machinery are only in the technology achieved.
Robert Heinlein (who was both a trained engineer and a trained military officer) made the better prediction of potential advances with his Mobile Infantry - ordinary men motivated and trained the way ordinary men have been trained and motivated since at least Roman times, equipped with enhanced 'suits' of armor powered and equipped with very advanced weapons, sensors, engines. He supposed systems that would make the most of ordinary humans instead of trying to breed extraordinary humans which would take more time and quickly reach the limitations of the biology.
The principle addition to that since he wrote Starship Troopers is that today we know that Camouflage is just about everything: if you can be spotted, you can be targeted by something Big Enough to kill you, no matter what kind of Supersuit or Genes you sport. So the major addition to Heinlein's concept would be masking, deceiving, 'stealth' and other technologies to make the trooper as invisible as possible to the enemy weapons.
Of course, that adds another problem to the game: how do you show off graphically an advanced weapon/soldier system that is trying very hard to be Invisible to every possible surveillance system? Another suspension of belief will be required . . .